JP5207916B2 - Wavefront aberration measuring apparatus and method - Google Patents

Description

  The present invention relates to a wavefront aberration measuring apparatus and method. Specifically, the present invention relates to a wavefront aberration measuring apparatus and method for measuring a change in wavefront aberration depending on a wavelength.

  Conventionally, measurement of wavefront aberration is used in clinical practice of dry eye, etc., and ophthalmic devices that are excellent in measurement of wavefront aberration have been developed. In addition, ophthalmic devices that analyze various optical characteristics based on measurement of wavefront aberration and scattering have been developed. Since the human eye responds to visible light, measurement with visible light is desirable, but since the eye to be measured feels dazzling, conventionally, measurement was performed with a single color of infrared light that is kind to the eyes. Further, the measurement of the chromatic aberration of the wavefront, that is, the change in the amount of aberration for each wavelength has not been made. (For example, see Patent Documents 1 to 3)

JP 2004-275697 A (paragraphs 0005 to 0056, FIGS. 1 to 14) Japanese Patent Laying-Open No. 2005-230328 (paragraphs 0005 to 0056, FIGS. 1 to 18) JP 2005-279022 A (paragraphs 0007 to 0113, FIGS. 1 to 17)

  However, depending on the eye to be examined, for example, in the case of cataracts or when a diffractive multifocal IOL is used, the change in optical characteristics in the visible range is large. There is a problem that wavefront aberration cannot be estimated, that is, chromatic aberration cannot be ignored.

  It is an object of the present invention to provide an apparatus and a method capable of measuring eye chromatic aberration.

  In order to solve the above-described problem, the wavefront aberration measuring apparatus 1 according to the first aspect includes a light source unit 11 that switches and emits light having a plurality of wavelengths as shown in FIGS. 1, 3, and 4, for example. The illumination optical system 10 that irradiates the fundus 81 of the eye 80 with the illumination light beam emitted from the light source unit 11 as spot light, the Hartmann plate 22 that divides the reflected light beam from the fundus 81 into a plurality of divided light beams, and the Hartmann A light receiving optical system 20 having a light receiving unit 21 that receives a plurality of divided light beams divided by the plate 22; a wavefront aberration calculating unit 901 that calculates wavefront aberrations for light of each wavelength received by the light receiving unit 21; A chromatic aberration calculator 902 for determining chromatic aberration of the wavefront based on the wavefront aberration at each wavelength determined by the wavefront aberration calculator 901.

  Here, the light source unit 11 that switches and emits light of a plurality of wavelengths has a plurality of light sources that emit light of different wavelengths, and may be configured to switch the light sources, and emits light of different wavelengths. A single light source may be used to change the emission wavelength. If comprised like this aspect, the chromatic aberration of eyes, ie, the wavefront aberration measuring apparatus which can measure the change of the amount of aberrations for every wavelength can be provided.

The wavefront aberration measuring apparatus according to the second aspect is the wavefront aberration measuring apparatus according to the first aspect, wherein the plurality of wavelengths include at least a wavelength in the near infrared region and a wavelength in the visible region.
Here, the light of a plurality of wavelengths may include one or more near-infrared wavelengths and one or more visible wavelengths. If comprised like this aspect, the wavefront aberration measuring apparatus which can measure the chromatic aberration of the eye with the light of a near infrared region and a visible region can be provided.

Further, the wavefront aberration measuring apparatus according to the third aspect is the same as the wavefront aberration measuring apparatus according to the first or second aspect, for example, as shown in FIGS. In the remeasurement determination unit 903 for determining whether the next measurement should be performed by adding or changing the wavelength, the remeasurement determination unit 903 determines that the next measurement is to be performed. The re-measurement determination unit 903 selects the wavelength to be added or changed, and the re-measurement determination unit 903 determines the next time based on the separation state or the blur state of the received light on the light receiving surface of the light receiving unit 21. The wavelength selection unit 904 selects one or a plurality of wavelengths to be added or changed in the next measurement based on the separation state or blurring state of the received light on the light receiving surface of the light receiving unit 21. To do.
Here, the separation or blur of the received light may occur when an IOL or the like is used for the eye 80 to be examined. In this case, the next measurement is performed depending on the situation. When a wavelength tunable laser is used as the light source, the wavelength selection unit 904 digitally selects a wavelength to be added or changed. With this configuration, it is possible to determine whether the next measurement is appropriate from the previous measurement results, and it is possible to select a wavelength suitable for the next wavefront aberration measurement. In addition, it is easy to find use of IOL or the like.

Further, the wavefront aberration measuring apparatus according to the fourth aspect is the same as the wavefront aberration measuring apparatus according to the first or second aspect. For example, as shown in FIGS. In the remeasurement determination unit 903 for determining whether the next measurement should be performed by adding or changing the wavelength, the remeasurement determination unit 903 determines that the next measurement is to be performed. In this case, the re-measurement determination unit 903 includes a wavelength selection unit 904 that selects a wavelength to be added or changed, and the remeasurement determination unit 903 performs the next measurement based on the change of the wavefront aberration obtained by the wavefront aberration calculation unit 901. The wavelength selection unit 904 adds or changes a single wavelength to be added or changed in the next measurement based on the change of the wavefront aberration in the plurality of wavelengths obtained by the wavefront aberration calculation unit 901. It selects a plurality of wavelengths.
Here, when the change of the wavefront aberration depending on the wavelength becomes large, it becomes difficult to estimate the wavefront aberration in the visible region from the wavefront aberration in the near infrared region. With this configuration, it is possible to determine whether the next measurement is appropriate from the previous measurement results, and it is possible to select a wavelength suitable for the next wavefront aberration measurement. In addition, it is easy to determine the difficulty of estimating the wavefront aberration in the visible range.

Further, the wavefront aberration measuring device according to the fifth aspect is the wavefront aberration measuring device according to the third or fourth aspect, wherein the wavelength selection unit 904 sequentially selects from long wavelengths when selecting the wavelength to be added or changed. .
If comprised in this way, data can be accumulate | stored in order of a wavelength, and the burden on the eye by visible light can be made as small as possible by measuring from near infrared light with few burdens to eyes.

Further, the wavefront aberration measuring apparatus according to the sixth aspect is the same as the wavefront aberration measuring apparatus according to the fourth aspect, except that the wavelength selecting unit 904 has a rough wavelength where the change due to the wavelength of the wavefront aberration obtained in the previous measurement is small. Where the change in the wavefront aberration due to the wavelength is large, the wavelength to be added or changed is selected at a fine wavelength interval.
If comprised in this way, the mode of the change by the wavelength of a wavefront aberration will be known exactly.

The wavefront aberration measuring apparatus according to the seventh aspect is the wavefront aberration measuring apparatus according to any one of the first to sixth aspects. For example, as shown in FIG. 1, the light source unit 11 emits light of different wavelengths. A plurality of light sources 111 and 112, a plurality of fibers 121 to 123 that allow light incident from an incident end to pass through and are emitted to an output end, and light incident from two fibers are combined and emitted to another fiber. And a plurality of fibers 121 to 123 and the single or plural fiber couplers 13 are connected in a tree shape, and light having different wavelengths emitted from the plural light sources 111 and 112 are respectively connected. Select the light of one wavelength that enters from the input end of different fibers 121 and 122 and emits light from any one of the light sources, and output the output end of one fiber. And it is configured to emit from 23.
If comprised in this way, when using a some light source for the light source part 11, switching of a wavelength can be made easy.

Further, the wavefront aberration measuring apparatus according to the eighth aspect is the same as the wavefront aberration measuring apparatus according to any one of the first to seventh aspects. For example, as shown in FIGS. Alternatively, a correction data storage unit 941 for storing data when wavefront aberration is measured at each wavelength as a wavefront aberration inside the apparatus using a model eye 85 that reflects a reflected light beam whose chromatic aberration has been corrected in advance. The chromatic aberration calculating unit 902 removes the wavefront aberration inside the apparatus at each wavelength stored in the correction data storage unit 941 from the wavefront aberration of each wavelength obtained by the wavefront aberration calculating unit 901, so that the eye to be examined The chromatic aberration of the wavefront of 80 is obtained.
Here, a range in which chromatic aberration can be practically ignored is included in order that chromatic aberration does not occur. The correction data storage unit 941 may be stored across a plurality of storage media as long as it can be read out as correction data. For example, the correction data storage unit 941 may be provided in the storage unit 94 or provided in the calculation unit 90. May be. If comprised like this aspect, the correction process which subtracts the chromatic aberration of the wave front inside an apparatus can be performed.

Further, the wavefront aberration measuring apparatus according to the ninth aspect is the same as the wavefront aberration measuring apparatus according to any one of the first to eighth aspects, as shown in FIGS. 12 and 13, for example, the wavelength of light emitted from the light source unit 11. Are determined in advance and switched automatically and continuously.
Here, automatic and continuous switching is possible, for example, by setting the wavelength order and switching timing in the control unit 91 and automatically controlling by a program or the like. In addition, it is preferable to select and measure sequentially from a long wavelength to a short wavelength. If it comprises like this aspect, a series of measurements can be made efficient.

Further, the wavefront aberration measuring apparatus according to the tenth aspect is the wavefront aberration measuring apparatus according to any one of the first to ninth aspects, for example, as shown in FIGS. 72, a fixation optical system 70 for irradiating the eye 80 with a fixation light beam having a wavelength in the visible range is provided, and the fixation target 72 is adjusted in position in the optical axis direction of the fixation optical system 70. The wavefront aberration calculating unit 901 obtains a spherical component for each wavelength of light received by the light receiving unit 21, and the chromatic aberration calculating unit 902 determines the position of the fixation target 72 based on the change of the spherical component with respect to the wavelength. The chromatic aberration of the wavefront from the eye 80 in the adjusted state is obtained.
If comprised in this way, the chromatic aberration match | combined with the eyes | visual_axis of the to-be-affected eye is calculated | required. In addition, when spherical aberration is used, the spherical IOL has a large amount of spherical aberration, and therefore it is easy to find the use of the spherical IOL.

In addition, the wavefront aberration measuring apparatus according to the eleventh aspect includes a light source unit 11 that switches and emits light of a plurality of wavelengths, as shown in FIG. 18, for example, and the first illumination light beam emitted from the light source unit 11 The first illumination optical system 10 that irradiates the fundus 81 of the eye 80 as a spot light, the Hartmann plate 22 that divides the reflected light beam from the fundus 81 into a plurality of divided light beams, and the plurality of light beams divided by the Hartman plate 22 The first light receiving optical system 20 having the first light receiving unit 21 that receives the divided light beam, the second illumination optical system 30 that irradiates the surface of the cornea 82 with the second illumination light beam, and the surface of the cornea 82. Wavefront aberration obtained by calculating the light of each wavelength received by the first light receiving unit 21 and the second light receiving optical system 40 having the second light receiving unit 41 that receives the reflected light beam from the first light receiving unit Wavefront aberration was received by the second light receiving unit 41 A wavefront aberration calculating unit 901 that obtains a wavefront aberration in the eye by removing the second wavefront aberration from the first wavefront aberration by setting the wavefront aberration obtained by calculating the light of the wavelength as the second wavefront aberration; A chromatic aberration calculation unit 902 that obtains chromatic aberration of the wavefront based on the wavefront aberration inside the eye of the wavelength.
With this configuration, it is possible to measure the chromatic aberration inside the eye excluding the influence of the curvature of the cornea.

The wavefront aberration measuring method of the twelfth aspect uses a light source unit 11 that switches and emits light of a plurality of wavelengths, for example, as shown in FIG. 4, and sets the wavelength emitted from the light source unit 11 ( S130), an illumination step of irradiating the fundus of the eye 80 with the illumination light beam emitted from the light source unit 11 as spot light (S141), and the Hartmann plate 22 for dividing the reflected light beam from the fundus 80 into a plurality of divided light beams. , A light receiving step (S142) for receiving a plurality of split light beams divided by the Hartmann plate 22, and a wavefront aberration calculating step for calculating and calculating wavefront aberration for each wavelength of light received in the light receiving step (S142). and S143), the remeasurement judging step (S150) determines whether measurements were made at a wavelength of a predetermined number, the measurement at a wavelength of a predetermined number of re-measurement determining step (S150) is not performed If determined, a remeasurement step for performing the setting step (S130), the illumination step (S141), the light receiving step (S142), the wavefront aberration calculation step (S143), and the remeasurement determination step (S150) again, and the remeasurement When it is determined in the determination step (S150) that the measurement has been performed at a predetermined number of wavelengths, the chromatic aberration calculation step for obtaining the chromatic aberration of the wavefront based on the wavefront aberration at each wavelength determined in the wavefront aberration calculation step (S143). ( S160 ).
Here, the predetermined number means the number of wavelengths used for measurement. When configured in this manner, it is possible to provide a wavefront aberration measuring method capable of measuring the chromatic aberration of the eye, that is, the change in the amount of aberration for each wavelength.

  In order to solve the above problem, the wavefront aberration measuring apparatus 1 according to the thirteenth aspect includes a plurality of wavelengths including at least near-infrared wavelength and visible wavelength, as shown in FIGS. The illumination optical system 10 that irradiates the fundus 81 of the eye 80 with the illumination light beam emitted from the light source unit 11 as spot light, and the reflected light beam from the fundus 81. A light receiving optical system 20 having a Hartmann plate 22 that is divided into a plurality of divided light beams, a light receiving unit 21 that receives the plurality of divided light beams divided by the Hartman plate 22, and light of each wavelength received by the light receiving unit 21 A wavefront aberration calculating unit 901 for calculating wavefront aberration, a separation state or blurring state of received light on the light receiving surface of the light receiving unit 21 at a wavelength in the near infrared region, a wavefront aberration obtained by the wavefront aberration calculating unit 901, Or Based on at least one of the changes of the wavefront aberration according to the wavelength obtained by the wavefront aberration calculator 901, measurement in the near-infrared wavelength is sufficient or insufficient, and the wavefront aberration at the visible wavelength is sufficient. When the remeasurement determination unit 903 that determines whether to perform measurement and the remeasurement determination unit 903 determine that the measurement in the near-infrared wavelength is sufficient, the wavefront aberration in the near-infrared wavelength is determined. A measurement result selection unit 906 that acquires the wavefront aberration at the visible wavelength as the measurement result when the measurement result is acquired and it is determined that the measurement is performed at the visible wavelength.

  Here, the light source unit 11 that switches and emits light of a plurality of wavelengths has a plurality of light sources that emit light of different wavelengths, and may be configured to switch the light sources, and emits light of different wavelengths. A single light source may be used to change the emission wavelength. In addition, the light of a plurality of wavelengths may include one or more near-infrared wavelengths and one or more visible wavelengths. When configured in this manner, it is possible to provide a wavefront aberration measuring apparatus that determines whether or not the measurement of the wavefront aberration is sufficient in the near-infrared region, and can perform the measurement in the visible region when the measurement is insufficient.

Further, the wavefront aberration measuring device according to the fourteenth aspect is the remeasurement in the wavefront aberration measuring device according to the thirteenth aspect when the spherical aberration of the wavefront aberration obtained by the wavefront aberration calculating unit 901 is larger than a predetermined value. The determination unit 903 determines to perform measurement at a visible wavelength.
Here, the spherical aberration may occur when a spherical IOL or the like is used for the eye 80 to be examined. In this case, measurement at a wavelength in the visible range is performed according to the magnitude of the spherical aberration. When configured in this manner, it is easy to find the use of the spherical IOL.

The wavefront aberration measuring device according to the fifteenth aspect is the wavefront aberration measuring device according to the thirteenth aspect, wherein the remeasurement determining unit 903 is in the visible region when the light received on the light receiving surface is separated into a plurality of points. It is determined that the measurement is performed at the wavelength.
Here, separation of the received light may occur when a diffractive multifocal IOL or the like is used for the eye 80 to be examined. When configured in this manner, it is easy to discover the use of a diffractive multifocal IOL.

Further, the wavefront aberration measuring apparatus according to the sixteenth aspect is the wavefront aberration measuring apparatus according to any one of the thirteenth to fifteenth aspects, for example, as shown in FIGS. 72, a fixation optical system 70 for irradiating the eye 80 with a fixation light beam having a wavelength in the visible region is included, and the fixation light beam includes a wavelength in the visible region for measurement emitted by the light source unit 11. A wavelength in a different region is selected.
With this configuration, the wavelength of the fixation optical system 70 can be prevented from overlapping the measurement wavelength.

Further, in the wavefront aberration measuring apparatus according to the seventeenth aspect, the wavefront aberration measuring apparatus according to the sixteenth aspect reflects the reflected light beam from the fundus 81 and transmits the fixation light beam as shown in FIG. A wavelength selective mirror 105 that separates a reflected light beam from the fundus 81 and a fixation light beam is provided.
With this configuration, the wavelength of the fixation optical system 70 and the wavelengths of the illumination optical system 10 and the light receiving optical system 20 used for measurement can be satisfactorily separated.

The wavefront aberration measuring apparatus according to the eighteenth aspect is the same as the wavefront aberration measuring apparatus according to any of the thirteenth to seventeenth aspects, for example, as shown in FIG. Preset and switch automatically.
Here, automatic switching is possible, for example, by setting the wavelength order and switching timing in the control unit 91 and automatically controlling by a program or the like. If it comprises like this aspect, a series of measurements can be made efficient.

The eye optical characteristic measurement device according to the nineteenth aspect includes a light source unit 11 that switches and emits light having a plurality of wavelengths including at least a wavelength in the near infrared region and a wavelength in the visible region, and is emitted from the light source unit 11. The illumination optical system 10 that irradiates the fundus 81 of the eye 80 as spot light, the Hartmann plate 22 that divides the reflected light beam from the fundus 81 into a plurality of divided light beams, and a plurality of light beams divided by the Hartman plate 22 Obtained by a light receiving optical system 20 having a light receiving unit 21 that receives a split light beam, a wavefront aberration calculating unit 901 that calculates wavefront aberration for light of each wavelength received by the light receiving unit 21, and a wavefront aberration calculating unit 901. An optical characteristic analysis unit 905 that analyzes optical characteristics of the eye 80 to be examined based on the wavefront aberration at each wavelength.
Here, the optical characteristics include wavefront aberration, refractive index, point spread coefficient (PSF), MTF (Modulation Transfer Function) indicating transfer characteristics of the eye to be examined, visual acuity, pupil diameter, contrast sensitivity, and the like. The eye optical characteristic measuring device includes a wavefront aberration measuring device. When configured in this manner, the optical characteristics can be measured by selecting a wavelength suitable for the measurement.

The wavefront aberration measuring method of the twentieth aspect uses a light source unit 11 that switches and emits light of a plurality of wavelengths including at least a wavelength in the near infrared region and a wavelength in the visible region, for example, as shown in FIG. A setting step (S330) for setting a wavelength in the near-infrared region emitted from the light source unit 11, an illumination step (S341) for irradiating the fundus 81 of the eye 80 with the illumination light beam emitted from the light source unit 11 as spot light, and Using the Hartmann plate 22 that divides the reflected light beam from the fundus 81 into a plurality of divided light beams, the light receiving unit 21 receives the plurality of divided light beams divided by the Hartman plate 22 and the light receiving step (S342). ), A wavefront aberration calculation step (S343) obtained by calculating wavefront aberration for the light of each wavelength received in step S3), and a separation state of received light on the light receiving surface of the light receiving unit 21 at a wavelength in the near infrared region, or Based on at least one of the blur condition, the wavefront aberration obtained in the wavefront aberration calculating step (S343), or the change of the wavefront aberration obtained in the wavefront aberration calculating step (S343) depending on the wavelength, the wavelength in the near infrared region In the remeasurement determination step (S400) and remeasurement determination step (S400) for determining whether the measurement is sufficient or insufficient and the wavefront aberration should be measured at the visible wavelength, the wavelength in the near infrared region If it is determined that the measurement at the wavelength is sufficient, the wavefront aberration at the near-infrared wavelength is obtained as a measurement result, and if it is determined that the measurement is performed at the visible wavelength, the wavelength of the visible wavelength is obtained. for light, a setting step (S430), the illumination step (S441), performs a receiving step (S442) and the wavefront aberration calculating step (S443), the wave front aberration at the wavelength of the visible region It is obtained as a measurement result and a measurement result selection step (S480).
If comprised in this way, it can be determined whether the measurement of a wavefront aberration is enough for the measurement in a near-infrared region, and the wavefront aberration measuring method which can perform a measurement in a visible region when it is inadequate can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the apparatus and method which can measure chromatic aberration of eyes can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
In the first embodiment, an example in which measurement is performed by switching between two light sources, a light source that emits light in the near infrared region and a light source that emits light in the visible region, will be described.

[Optical system configuration]
FIG. 1 shows a configuration example of an optical system of a wavefront aberration measuring apparatus 1 according to the first embodiment. The wavefront aberration measuring apparatus 1 includes an illumination optical system 10, a light receiving optical system 20, an anterior ocular segment illumination system 30, an anterior ocular segment observation system 40, a first adjustment optical system 50, and a second adjustment optical system. 60 and a fixation optical system 70. The light receiving optical system 20 includes a light receiving unit 21. For the eye 80, a retina (fundus) 81, a cornea (anterior eye portion) 82, and a crystalline lens 83 are shown.

Hereinafter, each part will be described in detail.
The illumination optical system 10 is for irradiating the fundus 81 of the eye 80 with the illumination light beam emitted from the light source unit 11 as spot light. The illumination optical system 10 includes, for example, a light source unit 11, a condenser lens 101, a diaphragm 102, a condenser lens 103, beam splitters 104 to 106, a condenser lens 107, and a rotary prism 108. The condensing lens 101 condenses the illumination light beam in the vicinity of the stop 102. Beam splitters 104 to 106 are disposed between the condenser lens 103 and the condenser lens 107. The beam splitter 104 includes a dichroic mirror that reflects the illumination light beam and transmits the reflected light beam from the fundus 81. The beam splitter 105 includes a wavelength selective mirror that reflects the illumination light beam and the reflected light beam and transmits the fixation light beam used in the fixation optical system 70. The beam splitter 106 includes a dichroic mirror that reflects the illumination light beam, the reflected light beam, and the fixation light beam and transmits the observation light beam used in the anterior eye portion observation system 40 and the second adjustment optical system 60. In addition, the rotary prism 108 is disposed in order to uniformize light caused by uneven reflection from the fundus 81 and the like. Further, by decentering the diaphragm 102, the incident position of the illumination light beam from the light source unit 11 to the eye 80 to be examined is changed in a direction orthogonal to the optical axis, and the vertex reflection of the lens and the cornea 82 is prevented and noise can be suppressed. In addition, the diaphragm 102 can perform so-called single-pass aberration measurement in which the aberration of the eye affects only the light receiving side. As described above, from the eye 80 to the beam splitter 106, the illumination optical system 10, the light receiving optical system 20, the fixation optical system 70, the common optical system of the anterior ocular segment observation system 40 and the second adjustment optical system 60, the beam splitter. 106 to the beam splitter 105 are a common optical system of the illumination optical system 10, the light receiving optical system 20 and the fixation optical system 70, and from the beam splitter 105 to the beam splitter 104 are a common optical system of the illumination optical system 10 and the light receiving optical system 20. It has become.

  FIG. 2 shows an example of filter characteristics of a beam splitter (wavelength selective mirror) 105 that reflects the illumination light beam and the reflected light beam and transmits the fixation light beam. The horizontal axis indicates the wavelength, and the vertical axis indicates the light transmittance. As the wavelengths of the light sources 111 and 112 of the illumination optical system 10, a wavelength having a transmittance of about 0% (reflectance of about 100%) such as 560 nm and 840 nm is selected, and the wavelength of the light source 71 of the fixation optical system 70 is 400 If a wavelength of about 100% transmittance at ˜530 nm is used, it can be used as a filter with good characteristics that reflects the illumination light beam and the reflected light beam and transmits the fixation light beam. Thereby, the wavelength of the fixation optical system 70 and the wavelengths of the illumination optical system 10 and the light receiving optical system 20 used for measurement can be well separated.

  The light source unit 11 emits light of a plurality of wavelengths, and switches and emits the light of a plurality of wavelengths. For example, light from a plurality of light sources 111 and 112 that emit light of different wavelengths is incident on the fibers 121 and 122, respectively, and the optical path is switched using the tree-type fiber coupler 13, and the exit end of one fiber 123 The light is emitted from. The wavelength is switched, that is, the optical path is switched by turning on and off the power sources of the light sources 111 and 112. Note that the mechanical shutter provided in front of the light sources 111 and 112 may be opened or closed, or the shutter may be opened and closed by an acousto-optic modulator (AOM). Wavelength switching is controlled by a wavelength selection signal (1 in ◯, 2 in ◯). Here, 840 nm in the near infrared region and 560 nm in the visible region were selected as the plurality of wavelengths. As the light source 111, an SLD (super luminescence diode) was used because it is desirable that the light source 111 has high spatial coherence in the near-infrared region, low temporal coherence, and high luminance. Further, as the light source 112, an LED (light emitting diode) is used because a sufficient amount of light is obtained in the visible range and is easy to handle. Even a laser with high coherence in both space and time can be used with a moderately reduced time coherence by inserting a rotating diffusion plate, a declination prism, or the like. If the branching of the light source and the fiber coupler is increased, it is possible to select at a plurality of wavelengths in the visible range and to measure at more wavelengths.

  The light receiving optical system 20 receives a reflected light beam from the fundus 81 of the eye 80 to be examined and guides it to the light receiving unit 21. The light receiving optical system 20 includes, for example, a light receiving unit 21, a Hartmann plate 22, a condensing lens 201, a diaphragm 202, a condensing lens 203, a reflecting plate 204, and a condensing lens 205. Further, from the eye 80 to the beam splitter 104, the illumination optical system 10 and the common optical system are used. In order to measure the spherical component, third-order astigmatism, and other higher-order aberrations of the eye 80 to be measured, the Hartmann plate 22 is a microlens for dividing the reflected light beam into at least 17 divided light beams. Having an array. As the micro lens array, for example, a plurality of micro Fresnel lenses arranged in a plane orthogonal to the optical axis is used. For the microlens array, a long focus or high sensitivity lens may be used, and a short focus or high density lens may be used. The reflected light beam from the fundus 81 is divided into a plurality of divided light beams by the Hartmann plate 22, and each divided light beam is condensed on the light receiving surface of the light receiving unit 21. The light receiving unit 21 receives a plurality of divided light beams divided by the Hartmann plate 22. The wavefront aberration is obtained by analyzing a photographed image based on the light reception signal (4 in the circle) received by the light receiving unit 21, and the chromatic aberration of the wavefront is obtained from the change of the wavefront aberration depending on the wavelength. The light reception signal (4 in the circle) is transmitted to the calculation unit 90. The condensing lens 201 converts the reflected light beam that has passed through the diaphragm 202 into a parallel light beam and guides it to the Hartmann plate 22. The reflection plate 204 is for making the direction of the optical axis of the reflected light beam toward the light receiving unit 21 coincide with the direction of the optical axis of the illumination light beam from the light source unit 11.

  The reflected light beam from the eye 80 follows the same optical path as the illumination light beam in paraxial direction to the beam splitter 104. However, in the single pass measurement, the respective light beam diameters are different, and the beam diameter of the illumination light beam is set to be considerably thinner than the reflected light beam. For example, the beam diameter of the illumination light beam may be about 1 mm at the pupil position of the eye 80 to be examined, and the beam diameter of the reflected light beam may be about 7 mm. Note that double-pass measurement can also be performed by appropriately arranging the optical system.

  The optical system moving unit 15 integrally moves a portion surrounded by a dotted line in FIG. 1 including the illumination optical system 10, the light receiving optical system 20, and a fixation optical system 70 described later. For example, assuming that the illumination light beam from the light source unit 11 is reflected by the fundus 81, the relationship in which the signal peak at the light receiving unit 21 due to the reflected light beam is maximized is maintained, and the signal peak at the light receiving unit 21 increases. Move to, and adjust to stop at the position where the intensity is maximum. In order to move them integrally, the illumination optical system 10, the light receiving optical system 20, and the fixation optical system 70 may be configured on one stage. In this case, when the adjustment distances of the respective optical systems are slightly different, it is preferable that fine adjustment can be performed separately. The illumination optical system 10, the light receiving optical system 20, and the fixation optical system 70 may be moved separately. The optical system moving means 15 is controlled by a movement control signal (3 in ○).

  The anterior ocular segment illumination system 30 irradiates the anterior segment 82 in a predetermined pattern using, for example, a ring-shaped light source 31 such as Placido ring (PLACIDO'S DISC) or kerat ring or a point light source. The placido ring is for projecting a pattern index composed of a plurality of concentric annular zones. When keratoling is used, a pattern only in the vicinity of the center of curvature of the cornea can be obtained from the kerato image. The wavelength of the light beam emitted from the ring light source 31 can be selected from a wavelength (for example, 940 nm) in a region different from the wavelength of the illumination light beam (here, 560 nm, 840 nm) in the illumination optical system 10. The ring-shaped light source 31 is controlled by a control signal (6 in a circle).

  The anterior ocular segment observation system 40 is for observing a reflected light beam that is irradiated by the anterior ocular segment illumination system 30 and reflected from the anterior segment 82 of the eye 80 to be examined. The anterior ocular segment observation system 40 includes, for example, a light receiving unit 41, a telecentric diaphragm 42, condenser lenses 401 to 403, and a beam splitter 404. Further, the optical system from the eye 80 to the beam splitter 106 is a common optical system with the illumination optical system 10 and the like. The light receiving unit 41 is constituted by a CCD, for example, and receives a pattern such as platid ring and kerat ring. The telecentric stop 42 is a stop for preventing an anterior ocular segment image from being blurred. The condensing lens 401 guides the reflected light beam to the light receiving unit 41 as a condensed light beam. The light receiving unit 41 transmits a light reception signal (7 within a circle) to the calculation unit 90. A beam splitter 404 disposed between the condensing lens 402 and the condensing lens 403 transmits a reflected light beam from the anterior ocular segment observation system 40 and reflects a light beam emitted from a second adjusting optical system 60 described later. Consists of.

  The first adjusting optical system 50 mainly adjusts the working distance, that is, adjusts the position of the eye 80 to be examined (the position of the illumination optical system 10 and the light receiving optical system 20 in the optical axis direction). , A light receiving unit 52 and condenser lenses 501 and 502. Here, the working distance adjustment is performed, for example, by irradiating the light beam emitted from the light source unit 51 as a parallel light beam toward the eye 80 to be inspected by the condensing lens 501 and reflecting the light beam reflected from the eye 80 to be inspected. This is performed by receiving light at the light receiving unit 52 via the. When the eye 80 to be examined is at an appropriate working distance, a spot image from the light source unit 51 is formed on the optical axis of the light receiving unit 52. On the other hand, when the eye 80 to be examined deviates back and forth from an appropriate working distance, the spot image from the light source unit 51 is formed above or below the optical axis of the light receiving unit 52. The light receiving unit 52 only needs to be able to detect a change in the light beam position in the plane including the light source unit 51, the optical axis, and the light receiving unit 52. For example, a one-dimensional CCD and a position sensing device (PSD) arranged in this plane. Etc. can be used. The light source unit 51 is controlled by a control signal (9 within a circle), and the light receiving unit 52 transmits a light reception signal (10 within a circle) to the calculation unit 90. The light reception signal (10 in the circle) is used for adjusting the working distance by the calculation unit 90.

  The second adjustment optical system 60 performs, for example, alignment adjustment in the X and Y directions of the eye 80 (in the plane perpendicular to the optical axes of the illumination optical system 10 and the light receiving optical system 20 in the vicinity of the eye 80). The light source unit 61 for alignment and the condenser lens 601 are provided. Further, from the eye 80 to the beam splitter 404, a common optical system with the anterior segment observation system 40 is used.

  The fixation optical system 70 is, for example, for projecting a target for fixation or clouding onto the eye 80 to be examined, and includes a light source unit (for example, a lamp) 71, a fixation target 72, and a condensing light. A lens 701 and a reflection plate 702 are provided. By irradiating the fundus 82 with the fixation target 72 with the light flux from the light source unit 71, the eye 80 is observed and the line of sight is stabilized on the fixation target 72. Further, the eye from the eye 80 to the beam splitter 105 is a common optical system with the illumination optical system 10 and the like. The reflecting plate 702 indicates the direction of the optical axis of the emitted light beam from the light source unit 71 in the fixation optical system 70, the direction of the optical axis of the illumination light beam from the light source unit 11 in the illumination optical system 10, and the light receiving unit in the light receiving optical system 20. This is for the purpose of matching the direction of the optical axis of the reflected light beam directed to 21. The light source unit 71 is controlled by a control signal (11 in a circle).

  Although the above-described optical system has been mainly described as a single path with a thin incident light beam, the present embodiment can also be applied to wavefront aberration measurement as a double path with a large incident light beam. At that time, the optical system is arranged in a double-pass configuration, but the measurement / calculation processing by the calculation unit 90 is the same.

  In the entire optical system, the fundus of the eye 80 to be examined, the fixation target 72 of the fixation optical system 70, the light source unit 11, and the light receiving unit 21 are conjugate. The pupil (iris) of the eye 80 to be examined, the rotary prism 108, the Hartmann plate 22 of the light receiving optical system 20, and the stop 102 of the illumination optical system 10 are conjugate.

[Electrical system configuration]
In FIG. 3, the structural example of the electric system of the wavefront aberration measuring apparatus 1 is shown.
The wavefront aberration measuring apparatus 1 includes a calculation unit 90, a control unit 91, an input unit 92, a display unit 93, a storage unit 94, a first drive unit 95, and a second drive unit 96.

  The calculation unit 90 calculates a wavefront aberration for the light of each wavelength received by the light receiving unit 21 and calculates the wavefront aberration, and the chromatic aberration of the wavefront based on the wavefront aberration at each wavelength determined by the wavefront aberration calculation unit 901. The chromatic aberration calculation unit 902 for determining whether or not the chromatic aberration of the wavefront to be calculated is sufficient for the measurement at the wavelength of the previous measurement or insufficient, and whether to perform the next measurement by adding or changing the wavelength is re-determined. When the measurement determination unit 903 and the remeasurement determination unit 903 determine that the next measurement is to be performed, each wavelength received by the wavelength selection unit 904, the light receiving unit 21, or the light receiving unit 41 that selects a wavelength to be added or changed. An optical characteristic analysis unit 905 that analyzes various optical characteristics related to the eye to be inspected from the wavefront aberration measured based on the light of the wavelength and other measurement data is provided. The optical characteristic analysis unit 905 analyzes, for example, a point spread coefficient (PSF), an MTF (Modulation Transfer Function) indicating transfer characteristics of the eye to be examined, visual acuity, pupil diameter, contrast sensitivity, and the like.

  The calculation unit 90 includes a light reception signal from the light receiving unit 21 of the light receiving optical system 20 (4 within the circle), a light reception signal from the light receiving unit 41 of the anterior ocular segment observation system 40 (7 within the circle), and the first The light receiving signal (10 in circles) is input from the light receiving unit 52 of the adjusting optical system 50. The calculation unit 90 is configured to receive optical characteristics (for example, wavefront aberration) of the eye 80 based on the light reception signal from the light receiving optical system 20 (4 in circle) and the light reception signal from the anterior ocular segment observation system 40 (7 in circle). Wavefront chromatic aberration). Further, the working distance of the eye 80 to be examined is calculated based on the light reception signal from the first adjustment optical system 50 (10 in the circle). The calculation unit 90 appropriately outputs signals or other signals / data corresponding to the calculation results to the control unit 91 that controls the optical system and the electric system, the display unit 93, and the storage unit 94, respectively.

  The control unit 91 controls turning on and off of the light sources 111 and 112 of the illumination optical system 10, controlling the optical system moving unit 15, and the first adjustment optical system 50 based on the signal from the calculation unit 90. Light source unit 51, light source unit 61 of second adjustment optical system 60, light source 31 of anterior segment illumination system 30, light source unit 71 of fixation optical system 70, first drive unit 95, and second drive unit 96. It is for controlling. The control unit 91 performs control based on a signal corresponding to the calculation result in the calculation unit 90. That is, a wavelength selection signal (1 in ◯, 2 in ◯) is transmitted to the light sources 111 and 112 of the illumination optical system 10 to control wavelength switching, and the light source unit 51 of the first adjustment optical system 50, Control signals to the light source unit 61 of the second adjustment optical system 60, the light source 31 of the anterior segment illumination system 30, and the light source unit 71 of the fixation optical system 70 (9 within ○, 5 within ○, and 6 within ○, respectively). 11) is transmitted and controlled, and a rotation control signal (8 within 8) is transmitted to control the rotation of the rotary prism 108 by driving the first drive unit 95. The driving unit 96 is driven to transmit a movement control signal (3 in circles) to the optical system moving unit 15. The control unit 91 performs various controls for exhibiting the function of the wavefront aberration measuring apparatus 1. Furthermore, automatic control may be performed with respect to switching of the wavelength of light emitted from the light source unit 11 using a control program.

  The input unit 92 includes a keyboard for an operator to input various data, and a pointing device for instructing buttons, icons, positions, areas, and the like displayed on the display unit 93. The display unit 93 displays measurement results, calculation results, analysis results, a window for the operator to input and instruct data, and the like. The storage unit 94 stores data relating to the eye 80 to be examined, data used for wavefront aberration calculation and correction, measurement setting data, and the like. It is also possible to store a control program for performing measurement automatically.

  The first drive unit 95 rotates the rotary prism 108 and outputs a rotation control signal (8 in circles) to an appropriate lens moving unit (not shown) to drive the lens moving unit. For example, based on the light reception signal (4 in the circle) input from the light receiving unit 21 input to the calculation unit 90, the second drive unit 96 includes the illumination optical system 10, the light receiving optical system 20, and the fixation optical system 70. The optical system moving means 15 for moving the main part integrally in the optical axis direction is driven, and the optical system moving means 15 is driven by outputting a movement control signal (3 in circle). The spherical component can be compensated for by moving the light receiving optical system 20 and the like in the optical axis direction.

[Measurement flow chart]
FIG. 4 shows an example of a flowchart of wavefront aberration measurement.
When the subject comes to the measurement position and the measurement is started, the wavefront aberration measuring apparatus 1 is aligned at a position where the eye 80 can be measured (S110). This alignment is performed by the first adjustment optical system 50 and the second adjustment optical system 60, and may be manual or automatic. Next, a trigger is made to start measurement (S120). The trigger is performed, for example, by an operation of a measurement start button from the input unit 92 by the operator. Note that the calculation unit 90 may receive the alignment end signal. According to the trigger, the illumination optical system 10, the light receiving optical system 20, the anterior ocular segment illumination system 30, the anterior ocular segment observation system 40, the fixation optical system 70, and the like are on standby. Next, the wavelength selection unit 904 of the calculation unit 90 sets the wavelength of the illumination light beam from the light source unit 11 of the illumination optical system 10 (S130). The wavelength selection unit 904 sets the order of one or a plurality of wavelengths used for measurement and the wavelength for measurement (this also sets a predetermined number, that is, the number of wavelengths used for measurement), and for each measurement. Select the wavelength to be used. Here, the light source 111 is a near-infrared light source (wavelength 840 nm), the light source 112 is a visible light source (wavelength 560 nm), the wavelength used for measurement is the wavelength of these light sources, and the predetermined number is two. In normal measurement, measurement with light in the visible range is dazzling, so it is measured at wavelengths in the near infrared range that are gentle to the eyes. If sufficient results can be obtained by measuring near-infrared light, it is desirable to only measure near-infrared light, and if sufficient results cannot be obtained by measuring near-infrared light, It is desirable to carry out measurement with light. In addition, when there are a plurality of wavelengths to be selected, it is desirable that the measurement be performed in the order of long wavelength to short wavelength because the burden on the eye can be minimized. Therefore, the measurement is first performed with the light source 111. The control unit 91 transmits a wavelength selection signal (1 in ◯, 2 in ◯) to the light sources 111 and 112 of the illumination optical system 10 to turn on the light source 111 and turn off the light source 112. Next, wavefront aberration is measured at a wavelength in the near infrared region (S140). The wavefront aberration measurement (S140) is as follows. First, the illumination optical system 10 irradiates the illumination light beam emitted from the light source unit 11 so as to be focused on the fundus 81 of the eye 80 as a spot light (S141). Next, in the light receiving optical system 20, the reflected light beam from the fundus 81 is divided into a plurality of divided light beams by the Hartmann plate, and the plurality of divided light beams are received by the light receiving unit 21 (S142). The light receiving unit 21 transmits a light reception signal (4 in a circle) to the calculation unit 90. Next, in the calculation unit 90, the wavefront aberration calculation unit 901 calculates wavefront aberration for light having a wavelength in the near infrared region received by the light receiving unit 21 (S143).

  After the wavefront aberration measurement (S140), the calculation unit 90 determines whether or not the remeasurement determination unit 903 has measured at a predetermined number of wavelengths (S150). Here, the predetermined number is two. When the re-measurement determining unit 903 determines that the number of wavelengths does not reach the predetermined number, that is, the light having a wavelength in the visible range has not been measured yet, the wavelength selection unit 904 again outputs the light from the light source unit 11. The wavelength of the illumination light beam is set (selected here) (S130). In this case, wavelengths are selected according to the order of wavelengths used for measurement set in the previous setting step (S130). Here, it is assumed that measurement is performed by the light source 112, and the control unit 91 transmits a wavelength selection signal (1 in ◯, 2 in ◯) to the light sources 111 and 112 of the illumination optical system 10, and turns off the light source 111. The light source 112 is turned on. Next, wavefront aberration is measured at a wavelength in the visible range (S140). The content of the wavefront aberration measurement (S140) is the same as the measurement of the wavefront aberration at the wavelength in the near infrared region (S141 to S143). After the measurement of wavefront aberration (S140), the remeasurement determination unit 903 determines whether the number of wavelengths has reached a predetermined number (S150). Wavefront aberration measurement is repeated until it is determined that the number of wavelengths has reached a predetermined number (S130 to S150). Here, since the predetermined number is 2, it is determined that the number of wavelengths has reached the predetermined number. When the re-measurement determination unit 903 determines that the number of wavelengths has reached a predetermined number, the chromatic aberration calculation unit 902 analyzes the wavefront chromatic aberration based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculation unit 901. Is performed (S160). Here, a difference due to a wavelength change from a wavefront aberration at a reference wavelength (for example, a measurement wavelength 560 nm close to d-line 587.56 nm) is obtained as chromatic aberration. The wavefront aberration at the reference wavelength is stored in the storage unit 94, and the chromatic aberration is obtained by subtracting the wavefront aberration at the reference wavelength from the wavefront aberration measured at each wavelength (here, 840 nm and 560 nm). For example, axial chromatic aberration and chromatic aberration at the wavefront are obtained with reference to a measurement wavelength of 560 nm close to the d-line (587.56 nm). When the chromatic aberration at each wavelength is obtained, the wavefront aberration measurement is terminated. In FIG. 4, the analysis ends with the analysis of chromatic aberration (S160), but the optical characteristics can also be analyzed based on the measurement result of the wavefront aberration and other measurement results. The optical characteristic analysis unit 905 analyzes, for example, PSF, MTF, visual acuity, pupil diameter, contrast sensitivity, and the like. These analysis results are used, for example, for remeasurement determination in the fifth embodiment or the tenth embodiment.

[Zernike analysis and RMS]
Zernike analysis is used to measure the wavefront aberration W (X, Y). Based on the tilt angle of the light beam obtained by the light receiving unit 21 via the Hartmann plate 22, the Zernike coefficient c _i ^2j-i , which is an important parameter for grasping the optical characteristics of the eye 80 to be examined, is calculated. The calculation unit 90 calculates the Zernike coefficient c _i ^2j−i in the wavefront aberration calculation unit 901, and uses this to obtain eye optical characteristics such as spherical aberration, coma aberration, and astigmatism.

FIG. 5 is a table in which measured values of wavefront aberration at wavelengths of 560 nm and 840 nm are displayed in Zernike coefficients. FIG. 6 is a graph showing Zernike coefficients of measurement examples of wavefront aberration at wavelengths of 560 nm and 840 nm. 5 and 6, c _i ^2j−i is expressed as Cik (k = 2j−1) or cik (k = 2j−1) (where i is a positive integer, k is positive or Negative integer). In this measurement example, it can be seen that there is a difference between the Zernike coefficients c _i ^2j−i of the wavelength 560 nm and the wavelength 840 nm, that is, the wavefront aberration W (X, Y).

Next, Zernike analysis will be described. A method for calculating the Zernike coefficients c _i ^2j-i from a generally known Zernike polynomial will be described. The Zernike coefficient c _i ^2j−i is an important parameter for grasping the optical characteristics of the eye 80 based on, for example, the tilt angle of the light beam obtained by the light receiving unit 21 via the Hartmann plate 22.
The wavefront aberration W (X, Y) of the eye 80 to be examined is expressed by the following expression using the Zernike coefficient c _i ^2j−i and the Zernike polynomial Z _i ^2j−i .

However, (X, Y) are the vertical and horizontal coordinates of the Hartmann plate 22.

The wavefront aberration W (X, Y) is expressed by (x, y) in the vertical and horizontal coordinates of the light receiving unit 21, the distance between the Hartmann plate 22 and the light receiving unit 21, and the moving distance of the point image received by the light receiving unit 21. Is (Δx, Δy), the following relationship holds.

Here, the Zernike polynomial Z _i ^2j−i is expressed by the following mathematical formula.

The Zernike coefficient c _i ^2j−i can be obtained with a specific value by minimizing the square error represented by the following equation.

  Where W (X, Y): wavefront aberration, (X, Y): Hartmann plate coordinates, (Δx, Δy): distance traveled by the point image received by the light receiving unit 21, f: Hartman plate 22 and light reception Distance to part 21.

In addition, the calculation unit 90 calculates the aberration amount RMS _i ^2j−i using the Zernike coefficient c _i ^{2j−i according} to the following equation.

[Optical characteristics analysis]
The optical characteristic analysis unit 905 analyzes, for example, a point spread coefficient (PSF), MTF (Modulation Transfer Function) indicating transfer characteristics of the eye 80, visual acuity, pupil diameter, contrast sensitivity, and the like. PSF and MTF are obtained from the output of the light receiving unit 21 based on the point light source image by the Hartmann plate. The PSF is stored in the storage unit 94, and visual acuity simulation is performed with reference to the PSF. A visual acuity simulation image can be obtained by superimposing the PSF on the retinal image obtained from the wavefront aberration (for example, convolution integration). These optical characteristics represent the condition of the eye 80 to be examined, facilitate the discovery of the use of the IOL, and are used to determine whether or not remeasurement should be performed.

The optical characteristic analysis unit 905 calculates the pupil function f (x, y) by the following equation based on the wavefront aberration W (X, Y). Here, k is a wave vector.

The optical characteristic analysis unit 905 calculates a luminance distribution function Land (x, y) of the Landolt ring (or an arbitrary image). Land (x, y) is two-dimensionally Fourier transformed to obtain a spatial frequency distribution FR (u, v). The spatial frequency distribution OTF of the eyeball is calculated based on the pupil function f (x, y), and the spatial frequency distribution FR (u, v) of the Landolt ring (or any image) and the spatial frequency distribution OTF (u, v of the eyeball). ) To obtain the frequency distribution OR (u, v) after passing through the optical system of the eye.
FR (u, v) × OTF (u, v) → OR (u, v)
Next, the optical characteristic analysis unit 905 obtains a luminance distribution image LandImage (X, Y) of the Landolt ring (or any image) by two-dimensional inverse Fourier transform of OR (u, v).

  Next, the optical characteristic analysis unit 905 obtains the previously obtained PSF with reference to the storage unit 94, and convolves the obtained PSF with LandImage (X, Y) to generate a new simulation image of the retina image. obtain.

The optical characteristic analysis unit 905 performs template matching corresponding to the Landolt ring original image. A template image is set, and such a template image is stored in the storage unit 94 corresponding to the identifier indicating the size of the Landolt ring. The optical characteristic analysis unit 905 reads the template image from the storage unit 94 according to the set size of the Landolt ring, and obtains the spatial frequency distribution Temp (x, y). Next, a two-dimensional Fourier transform FT (u, v) of Temp (x, y) is obtained. A two-dimensional Fourier transform OR (u, v) of the spatial frequency distribution of the target image data obtained by simulation of the retina image is obtained, and OR (u, v) and the spatial frequency distribution FT (u, v) of the template are expressed by the following equations. Thus, OTmp (u, v) is obtained.
OR (u, v) × FT (u, v) → OTmp (u, v)

  The optical characteristic analysis unit 905 performs two-dimensional inverse Fourier transform on OTmp (u, v) to obtain TmpIm (X, Y) (4a × 4a complex number matrix). The maximum value of the absolute value of TmpIm (X, Y) is acquired and set as the score n. By taking such a correlation, if the simulation target image is close to the original image, the score is high, and if it is blurred, the score is lowered accordingly.

  The optical characteristic analyzer 905 can calculate contrast sensitivity as a visual acuity simulation. Mopt (r, s) which is the MTF of the eyeball optical system is obtained based on the wavefront aberration, and the contrast sensitivity is calculated based on the obtained MTF. Further, the calculated contrast sensitivity is displayed on the display unit 93 or stored in the storage unit 94.

  Next, calculation of MTF (Modulation transfer function) will be described. The MTF is an index indicating the transfer characteristic of the spatial frequency and is widely used to express the performance of the optical system. For example, the MTF can be predicted in appearance by obtaining transfer characteristics for 0 to 100 sinusoidal gray gratings per degree. As described below, a monochromatic MTF or a white MTF may be used.

First, the monochromatic MTF is calculated from the wavefront aberration W (x, y). Note that W (x, y) is an input value (measured value), and corneal wavefront aberration obtained from the corneal shape can be used as the corneal aberration. When obtaining the monochromatic MTF, the optical characteristic analysis unit 905 obtains the pupil function f (x, y) from the wavefront aberration as follows.
f (x, y) = e ^{ikW (x, y)}
(I: imaginary number, k: wave vector (2π / λ), λ: wavelength)
At this time, (e ^−arp ) ² (a is about 0.05, for example) may be applied in consideration of the Styles Crawford effect. Here, _{r p} is the radius of the pupil.

The optical characteristic analysis unit 905 obtains the amplitude distribution U (u, v) of the point image by the Fourier transform of the pupil function f (x, y) as follows:
(Λ: wavelength R: distance from pupil to image point (retina) (u, v): coordinate value (x, y) in plane perpendicular to optical axis with image point O as origin Coordinate value)
The arithmetic unit 210 multiplies U (u, v) and its complex conjugate to obtain I (u, v) which is a point image intensity distribution (PSF) by the following equation.
I (u, v) = U (u, v) U ^* (u, v)

Next, the optical characteristic analysis unit 905 obtains the OTF by normalizing the PSF by Fourier transform (or autocorrelation) as in the following equation.

Also, since the size of OTF is MTF,
MTF (r, s) = | OTF (u, v) |
Holds.

Next, the white light MTF is calculated based on the monochromatic MTF obtained as described above. In order to obtain the white light MTF, first, the MTF at each wavelength is weighted and added. Here, since the above-described MTF has a different value for each wavelength, when the MTF at the wavelength _λ is expressed as MTF _λ ,

Here, the visible light is heavily weighted for calculation.
Specifically, assuming that the three primary colors (RGB) of red, green, and blue are, for example, 656.27 nm: 1, 587.56 nm: 2, and 486.13 nm: 1,
MTF (r, s) = ( 1 × MTF 656.27 + 2 × MTF 587.56 + 1 × MTF 486.13) / (1 + 2 + 1)
It becomes.

Further, since the white light MTF is measured at only one wavelength (840 nm), it may be obtained by correcting other wavelengths based on this measurement result and correcting to white. Specifically, the MTF at each wavelength is the amount of deviation from the wavefront aberration W ₈₄₀ (x, y) at each wavelength 840 nm by the model eye when the measurement wavelength is 840 nm in the case of eye aberration, for example. Is obtained by measuring the chromatic aberration W _Δ (x, y) corresponding to the above, adding W ₈₄₀ (x, y) to the chromatic aberration W _Δ (x, y), and calculating the MTF from this wavefront aberration. That is,
W _λ (x, y) = W ₈₄₀ (x, y) + W _Δ (x, y)
It becomes.

  Further, the white light PSF can be calculated based on PSF = I (u, v) obtained as described above. In order to obtain the white light PSF, first, as in the case of obtaining the white light MTF, the PSF at each wavelength may be weighted and added. Weighting uses, for example, the visibility characteristics for each wavelength, or in the case of elderly people, the crystalline lens may be yellowed, so by weighting using the visibility characteristics for the yellowed eyes, It can be used for objective evaluation of appearance according to each eye.

  FIG. 7 shows an example of white PSF. The circle is a white PSF contour.

  FIG. 8 shows an example of a visual acuity simulation image. FIG. 8A shows an original image, and FIG. 8B shows a simulation image. A visual acuity simulation image can be obtained by referring to the PSF stored in the storage unit 94 and superimposing the PSF on the retinal image obtained from the wavefront aberration (for example, convolution integration). The contrast sensitivity of the simulation image is lower than that of the original image.

Next, contrast sensitivity will be described. The contrast sensitivity is expressed by the following formula.
(See, for example, Peter G. Barten: Contrast Sensitivity of the Human Eye and Its Effects on Image Quality. SPIE, Dec 1999)

Here, each parameter is as follows. M _opt (r, s): MTF of eyeball optical system, k: S / N ratio: 3, T: weighting time of nervous system: 0.1 sec, X ₀ : viewing angle of object: 3.8 deg, X _max : space Weighted maximum viewing angle: 12 deg, N _max : Weighted maximum frequency: 15 cycles, η: Quantum efficiency of eye photoreceptor: 0.3, p: Photon conversion factor (CRT) of light source: 1.24 (liquid crystal E: Retinal illuminance (Trand): 50 (cdm ² ) × r ² π (mm) = 50 r ² π (td) (r: pupil radius) 100 or less, Φ ₀ : Spectral density of nervous system noise: 3 × 10 8 sec · deg ² , u ₀ : Spatial frequency of side suppression: 7 cycles / deg. By using this equation, it is possible to predict the contrast sensitivity of the entire visual system in consideration of other elements (for example, the nervous system), not the contrast sensitivity of the eyeball optical system.
By obtaining the contrast sensitivity of the entire visual system corresponding to the spatial frequency, for example, the appearance of the fringe target can be predicted. Moreover, the ophthalmologist or the like can compare the contrast sensitivity displayed on the display unit with the sensitivity by subjective measurement, for example.

  As described above, according to the present embodiment, it is possible to provide an apparatus and a method capable of measuring the chromatic aberration of the eye in the near-infrared and visible light, that is, the change in the amount of aberration for each wavelength.

[Second Embodiment]
1st Embodiment demonstrated the example which uses the light source part 11 of the illumination optical system 10 for a total of 2 light sources, 1 light source which light-emits the light of a near infrared region, and 1 light source which light-emits light of a visible region. However, in the second embodiment, the light source unit 11 of the illumination optical system 10 has a total of four light sources, one light source that emits light in the near infrared region and three light sources that emit light having different wavelengths in the visible region. An example will be described in which measurement is performed by sequentially switching them. The same reference numerals are used for the same parts as those in the first embodiment, and redundant description is omitted (the same applies to the following embodiments). Differences from the first embodiment will be mainly described. Regarding the configuration of the optical system (see FIG. 1), LEDs that emit red, green, and blue light as three light sources that emit light in the visible range, or F-line (486.13 nm) and d-line (587.56 nm) , E-line (546.07 nm), C-line (656.27 nm) (of which 3 wavelengths are used) or the like, or a laser or SLD can be used. Lights from four light sources are respectively incident on four fibers, a four-branch coupler is used as a tree-type fiber coupler, the optical path is switched, and the light is emitted from the exit end of one fiber. As for the wavefront aberration measurement flowchart (see FIG. 4), in the wavelength setting step (S130), the wavelength selection unit 904 sets the four wavelengths used for measurement and the order of measurement (the predetermined number is also set to 4). The wavelength used for the measurement is selected in the set order. The remeasurement determination unit 903 determines that the measurement has been performed at a predetermined number of wavelengths after the measurement at the four wavelengths, and then the chromatic aberration calculation unit 902 analyzes the chromatic aberration. The chromatic aberration at this time is calculated by selecting one wavelength in the measurement light, or by performing a polynomial fitting or the like for each Zernike coefficient on the measurement result for each wavelength and using the d-line (587.56 nm) as a reference. Other configurations and processing flow are the same as those in the first embodiment, and an apparatus and method for measuring eye chromatic aberrations in the near-infrared and visible light, that is, changes in the amount of aberration for each wavelength, are provided. it can. In addition, it is also possible to obtain chromatic aberration at a large number of wavelengths by using a large number of light sources and multi-branch couplers. Further, when a plurality of light sources are used for the light source unit 11, the wavelength can be easily switched.

[Third Embodiment]
In the third embodiment, a wavelength tunable laser is used as the light source unit 11 of the illumination optical system 10, and light of three wavelengths different from each other in the near infrared region and the visible region is selected, and these wavelengths are switched. An example of measurement will be described. The difference from the second embodiment is that measurement is performed by switching the wavelength of light emitted from the wavelength tunable laser without using a tree-type fiber coupler. Switching of the emission wavelength from the light source unit 11 is performed, for example, by replacing a filter that transmits only the wavelength to be measured, or by using a wavelength variable filter, and other configurations and processes are the same as in the second embodiment. It has the same effect. It is also possible to use a combination of two wavelength tunable lasers and a two-branch type fiber coupler. Further, by using a large number of filters, it is possible to obtain chromatic aberration at a large number of wavelengths.

  FIG. 9 shows an example of bandpass characteristics of a liquid crystal wavelength tunable filter (see Japanese Patent Application Laid-Open No. 2006-158547) as the wavelength tunable filter. The horizontal axis represents wavelength (nm), and the vertical axis represents transmittance (%). The liquid crystal wavelength tunable filter can select the transmission wavelength in the range of 400 to 720 nm by changing the voltage applied to the liquid crystal. The figure shows how the transmitted light changes when the transmission center wavelength is changed by 10 nm. The wavelength width of the transmitted light is about 20 nm, and the peak value of the amount of transmitted light increases almost monotonously with the increase in wavelength. Since this filter can cover the visible range, the light source unit 11 can be constituted by two filters in the near infrared range and the visible range, a two-branch coupler, and this filter.

  FIG. 10 shows a configuration example of the liquid crystal wavelength tunable filter. The liquid crystal wavelength tunable filter selects a wavelength by combining several stages of liquid crystal tunable filters (LCTF: Liquid Crystal Tunable Filter). One LCTF is composed of a polarizing plate with a fixed wavelength plate and a liquid crystal variable wavelength plate sandwiched between them. The angle between the fixed wavelength plate and the polarizing plate of the liquid crystal variable wavelength plate is the difference in the optical path length between the generated ordinary ray and extraordinary ray. It is fixed at 45 degrees so that it can be controlled by a liquid crystal variable wavelength plate.

When the thickness of one wave plate is d, the optical path length difference R between the ordinary ray and the extraordinary ray is expressed by the following equation.
R = d × (n (e) −n (o))
Here, n (e) is the refractive index for ordinary light, and n (o) is the refractive index for extraordinary light. The optical path length difference R is changed by combining the fixed wavelength plate and the liquid crystal variable wavelength plate and changing the voltage applied to the liquid crystal variable wavelength plate. Light having an optical path length difference R is extracted by a polarizing plate in a 45-degree direction to form an interference filter.
The total transmittance T is expressed by the following equation with the wavelength being λ, and varies with the optical path length difference R.
T = (1/2) cos ² (πR / λ)

  FIG. 11 shows an example of the wavelength selection method of the liquid crystal wavelength tunable filter. In order to reduce the wavelength width to be output, a combination of wave plates having different thicknesses are stacked in several stages (six stages in the example in the figure) to realize a wavelength width of 20 nm. FIG. 11A shows the filter characteristics of each of the six stages of LCTFs. FIG. 11B shows the filter characteristics of a liquid crystal wavelength tunable filter in which six stages of LCTFs are stacked. By changing the voltage applied to the liquid crystal variable wavelength plate of each LCTF, the transmission center wavelength can be arbitrarily changed at high speed, and light having an arbitrary wavelength component can be extracted. Since the liquid crystal wavelength tunable filter is affected by the polarization direction of incident light, when using polarized light, alignment corresponding to the polarization angle of the incident light is necessary. Even in this case, the light emitted from the liquid crystal wavelength tunable filter is maintained in the same polarization direction as the incident light.

[Fourth Embodiment]
In the first embodiment, after selecting one or a plurality of wavelengths to be measured, an example in which measurement is performed once for each of these wavelengths has been described. However, in the fourth embodiment, continuous measurement is repeatedly performed. An example of performing is described. For example, the control unit 91 generates a timing pulse, transmits a switching signal to the light source unit 11 based on the timing pulse, and is programmed to transmit a light reception signal to the wavefront aberration calculation unit 901, thereby repeatedly and continuously. Measurement can be performed. Further, the program is stored in the storage unit 94 and is read out and used by the control unit 91. Other apparatus configurations are the same as those in the first embodiment.

  FIG. 12 shows an example of a flowchart of wavefront aberration measurement in the present embodiment. Differences from the first embodiment (see FIG. 4) will be mainly described. Next to the alignment (S110) of the wavefront aberration measuring apparatus 1, the measurement time is initially set (S115). For example, the measurement time is set to 40 seconds from the input unit 92 using a keyboard or the like. The set measurement time is stored in the storage unit 94. The measurement start trigger (S120) and the wavefront aberration measurement loop from the wavelength setting (S130) of the light source in the wavelength selection unit 904 to the determination of the number of wavelengths in the remeasurement determination unit 903 (S150) are the first embodiment. It is the same. If the remeasurement determination unit 903 determines that the number of wavelengths has reached a predetermined number, then the remeasurement determination unit 903 determines whether the measurement time has ended (S152). When the remeasurement determination unit 903 compares the time required for measurement with the measurement time stored in the storage unit 94 and determines that the time required for measurement is less than the measurement time stored in the storage unit 94, The wavefront aberration measurement loop from the wavelength setting of the light source in the wavelength selection unit 904 (S130) to the determination of the number of wavelengths in the remeasurement determination unit 903 (S150) is repeated. When it is determined that the time required for the measurement is equal to or longer than the measurement time stored in the storage unit 94, the measurement of the wavefront aberration is completed (S154). The next analysis of chromatic aberration (S160) is the same as in the first embodiment, but the measurement at each wavelength is repeated and continuously performed, so that a plurality of data for each wavelength is used to change over time. Measurement and statistical processing. In addition, the order of the wavelengths of the light emitted from the light source unit 11 is determined in advance and automatically controlled by a program or the like, so that a series of measurements can be made efficient.

  FIG. 13 shows an example of the timing of the control signal when measurement is repeated continuously. The controller 91 generates a timing signal pulse using a CCD. (A) shows timing signal pulses. For example, the pulse interval is 30 msec. The control unit 91 transmits a wavelength selection signal (1 in ◯, 2 in ◯) alternately to the light source 111 and the light source 112 for each timing signal pulse, and controls turning on and off of the light source 111 and the light source 112. (B) shows the wavelength selection signal to the light source 111 (1 in the circle), and (c) shows the wavelength selection signal to the light source 112 (2 in the circle). The light source 111 and the light source 112 emit light while a wavelength selection signal (1 in ◯, 2 in ◯) is transmitted, irradiates the eye 80 to be inspected by the illumination optical system 10, and the reflected light flux is received by the light receiving unit 21. The received light signal (4 in the circle) is transmitted to the calculation unit 90. In the calculation unit 90, the wavefront aberration calculation unit 901 receives the received light signal and calculates and calculates the wavefront aberration. (D) shows the received light signal (4 in the circle). The received light signal (4 in the circle) is transmitted by distinguishing signals at different wavelengths by a plus signal and a minus signal. These signals are repeatedly transmitted continuously, and measurements are continuously performed repeatedly at two wavelengths. It is also possible to increase the number of light sources to 3 or more and repeat measurement continuously. In this case, the received light signal is divided into three or more levels, for example.

[Fifth Embodiment]
In the first embodiment, in setting the wavelength of the illumination optical system 10 (S130), the wavelength selection unit 904 performs the setting only once when setting the wavelength used for measurement and the order of measurement. Although an example in which measurement is performed once at one wavelength has been described, in the present embodiment, an example in which setting is performed twice or more and a wavelength to be used is added or changed will be described. For example, the re-measurement determination unit 903 determines whether the wavefront aberration to be obtained is sufficient for the measurement at the previous measurement wavelength, or is insufficient, and whether the next measurement should be performed by adding or changing the wavelength. . Therefore, the light source unit 11 of the illumination optical system 10 uses a plurality of light sources that emit light of different wavelengths, uses a tree-type fiber coupler, and performs measurement by sequentially switching light of different wavelengths. Other apparatus (optical system and electrical system) configurations are the same as those in the first embodiment.

  FIG. 14 shows an example of a flowchart of wavefront aberration measurement in the fifth embodiment. Differences from the first embodiment (see FIG. 4) will be mainly described. First, an example will be described in which the near-infrared wavelength (840 nm) is set first, and then the visible wavelength (560 nm) is set. The alignment (S110) and measurement start trigger (S120) of the wavefront aberration measuring apparatus 1 are the same as those in the first embodiment. Next, in the wavelength setting (S130) of the light source in the wavelength selection unit 904, the wavelength is first set to the near-infrared wavelength (840 nm), and the predetermined number is set to 1. In normal measurement, since measurement with visible light is dazzling, measurement is performed at wavelengths in the near-infrared region that are gentle to the eyes. If sufficient results can be obtained by measuring near-infrared light, it is desirable to only measure near-infrared light, and if sufficient results cannot be obtained by measuring near-infrared light, It is desirable to carry out measurement with light. Therefore, at first, the wavelength is set to the near-infrared region, and measurement is performed with the light source 111. The control unit 91 transmits a wavelength selection signal (1 in ◯, 2 in ◯) to the light sources 111 and 112 of the illumination optical system 10 to turn on the light source 111 and turn off the light source 112. Next, wavefront aberration is measured at a wavelength in the near infrared region (S140). In the wavefront aberration measurement (S140), the fundus 81 is irradiated with the illumination light beam (S141), the reflected light beam is received by the light receiving unit 21 (S142), and the wavefront aberration calculating unit 901 obtains the wavefront aberration (S143). Next, the calculation unit 90 determines whether or not the remeasurement determination unit 903 has measured at a predetermined number of wavelengths (S150). When it is determined that the measurement is not performed at the predetermined number of wavelengths, the process returns to the wavelength setting of the light source (S130), and the loop is followed until it is determined that the measurement is performed at the predetermined number of wavelengths. Here, since the predetermined number is 1, the remeasurement determination unit 903 determines that the measurement has been performed at the predetermined number of wavelengths. Next, the re-measurement determination unit 903 determines whether the measurement at the previous measurement wavelength is sufficient or insufficient and whether the next measurement should be performed by adding or changing the wavelength (S155).

  If the re-measurement determination unit 903 determines that the next measurement is to be performed, the process returns to the light source wavelength setting (S130), and the wavelength selection unit 904 sets the wavelength to be added or changed. Here, the wavelength is set to a visible wavelength (560 nm), and the predetermined number is set to 1. It is assumed that measurement is performed with the light source 112, and the control unit 91 transmits a wavelength selection signal (1 in ◯, 2 in ◯) to the light sources 111 and 112 of the illumination optical system 10, turns off the light source 111, and turns off the light source 112. Light. Next, wavefront aberration is measured at a wavelength in the visible range (S140). In the wavefront aberration measurement (S140), the fundus 81 is irradiated with the illumination light beam (S141), the reflected light beam is received by the light receiving unit 21 (S142), and the wavefront aberration calculating unit 901 obtains the wavefront aberration (S143). Next, the calculation unit 90 determines whether or not the remeasurement determination unit 903 has measured at a predetermined number of wavelengths (S150). When it is determined that the measurement is not performed at the predetermined number of wavelengths, the process returns to the wavelength setting of the light source (S130), and the loop is followed until it is determined that the measurement is performed at the predetermined number of wavelengths. Here, since the predetermined number is 1, the remeasurement determination unit 903 determines that the measurement has been performed at the predetermined number of wavelengths. In this case, next, the re-measurement determination unit 903 determines whether the measurement at the wavelength of the previous measurement is sufficient or insufficient, and whether the next measurement should be performed by adding or changing the wavelength ( S155). If the remeasurement determination unit 903 determines that the next measurement is to be performed, the process returns to the wavelength setting (S130) of the light source, and the wavelength selection unit 904 selects the wavelength to be added or changed. If the re-measurement determination unit 903 determines that the measurement at the wavelength of the previous measurement is sufficient, the wavefront based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculation unit 901 in the chromatic aberration calculation unit 902 The chromatic aberration is analyzed (S160). For analysis of chromatic aberration, for example, wavefront aberration was measured at the F-line (486.13 nm), d-line (587.56 nm), e-line (546.07 nm), C-line (656.27 nm), or a wavelength close to these. In this case, axial chromatic aberration and chromatic aberration at the wavefront are obtained with reference to the d-line or a wavelength close to this (560 nm).

  As an example in which chromatic aberration occurs in FIG. 15, the paraxial focal point of the intersection with the optical axis at the light at each incident position on the pupil on the y-axis (vertical direction of the eye) in the plane including the optical axis. The example which graphed the deviation | shift amount (spherical aberration) from a position for every wavelength is shown. The horizontal axis indicates the amount of deviation (mm) from the paraxial focal position, and the vertical axis indicates the relative position on the y-axis on the pupil where the light ray is incident (analysis pupil radius is 1). This is an example of 7 wavelengths (500 nm to 850 nm). Different chromatic aberration is obtained for each wavelength. Thereby, the difference in the characteristics of spherical aberration for each wavelength and the degree of chromatic aberration are known.

  In the re-measurement determination unit 903, as a criterion for determining whether or not the measurement at the wavelength of the previous measurement is sufficient or insufficient and whether the next measurement should be performed by adding or changing the wavelength (S155). For example, the determination can be made based on the separation state or blurring state of the received light on the light receiving surface of the light receiving unit 21 of the light receiving optical system 20. That is, when the spot of the received light is separated, when the degree of blur is large, it is determined to remeasure. Further, for example, the determination can be made based on the change of the wavefront aberration at a plurality of wavelengths obtained by the wavefront aberration calculator 901. That is, it is determined to measure again when the change due to the wavelength is large. For example, when the wavefront aberration in the visible region cannot be predicted from the change due to the wavelength, it is determined to measure again. Thereby, it is possible to determine whether or not the next measurement is appropriate from the previous measurement results, and it is possible to select a wavelength suitable for the next wavefront aberration measurement.

  FIG. 16 is a diagram for explaining the determination of the degree of blur. FIG. 16A shows an example of a blurred state of received light on the light receiving surface of the light receiving unit 21. For example, as shown in FIG. 16B, the degree of blur can be evaluated by the area of the half-value portion in the point image intensity distribution (PSF), and whether the area of the half-value portion is compared with a threshold value and measured again. Can be determined. The separation or blurring of the received light may occur when a diffractive IOL or the like is used for the eye 80 to be examined. Therefore, it is easy to find the use of a diffractive IOL or the like from the situation of separation or blur of received light.

[Sixth Embodiment]
In the fifth embodiment, in the setting of the wavelength of the illumination optical system 10 (S130), the wavelength selection unit 904 performs the setting twice or more, first sets the near-infrared wavelength (840 nm), and then visible. In the sixth embodiment, an example is described in which the near-infrared wavelength is first set and then the visible wavelength is set to three wavelengths. Differences from the fifth embodiment will be mainly described. LEDs that emit red, green, and blue light as three light sources that emit light in the visible range, or F line (486.13 nm), d line (587.56 nm), e line (546.07 nm), C line ( 656.27 nm) or the like (of which 3 wavelengths are used) or SLD can be used. Lights from four light sources are incident on four fibers, respectively, and a four-branch coupler is used as a tree-type fiber coupler to switch the optical path, and the light is emitted from the exit end of one fiber. Also, it is possible to use eight light sources and eight branch couplers, or sixteen light sources and 16 branch couplers. If the wavefront aberration measurement re-measurement determination unit 903 determines that the next measurement should be performed in the determination of whether or not the next measurement should be performed (S155), the wavelength setting step (S130). The wavelength selection unit 904 selects a wavelength to be added or changed. Here, the wavelength selection unit 904 sets the three wavelengths used for measurement and the order of measurement (a predetermined number is also set to 3), and selects the wavelengths used for measurement in the set order. Further, in the determination (S155) whether or not the next measurement should be performed after the second time in the remeasurement determination unit 903, it can be determined that the next measurement should be performed again. In this case, more wavelengths can be set in the third and subsequent wavelength settings (S130). It is also possible to set the same wavelength by overlapping the previous wavelength setting and the subsequent wavelength setting. Note that the wavelength selection unit 904 adds or changes the wavelength at a coarse wavelength interval where the change due to the wavelength of the wavefront aberration obtained in the previous measurement is small, and at a fine wavelength interval where the change due to the wavelength of the wavefront aberration is large. When is selected, the state of the wavefront aberration depending on the wavelength can be accurately understood.

FIG. 17 shows an example of a chromatic aberration graph of each Zernike coefficient when measurement is performed at multiple wavelengths. FIG. 17A shows an example of the Zernike coefficient c ₂ ^-2 , and FIG. 17B shows an example of the Zernike coefficient c ₂ ⁰ . This chromatic aberration is obtained by subtracting the wavefront aberration at the d-line (587.56 nm) from the measured value at each wavelength with reference to the wavefront aberration at the d-line (587.56 nm). The Zernike coefficient changes between wavelengths of 500 nm to 1000 nm. The graph displays the result of each Zernike coefficient for each wavelength by performing polynomial fitting or the like.

[Seventh Embodiment]
In the seventh embodiment, an example of measuring chromatic aberration in the eye will be described. In the present embodiment, the fundus 81 is irradiated with the illumination light beam (first illumination light beam) of the illumination optical system (first illumination optical system) 10, and the fundus 81 is received by the light receiving optical system (first light receiving optical system) 20. In addition to receiving the reflected light beam from the light receiving unit 21 (first light receiving unit), the illumination light beam (second illumination light beam) of the anterior ocular segment illumination system (second illumination optical system) 30 is cornea 82. The reflected light beam from the cornea 82 is received by the light receiving part (second light receiving part) 41 by the anterior ocular segment observation system (second light receiving optical system) 40. As a result, the wavefront aberration (first wavefront aberration) from the fundus 81 and the corneal aberration (second wavefront aberration) from the cornea 82 are both measured, and the cornea from the wavefront aberration (first wavefront aberration) from the fundus 81 is measured. By subtracting the corneal aberration (second wavefront aberration) from 82, the wavefront aberration inside the eye can be obtained. By obtaining this for each wavelength, the chromatic aberration inside the eye can be obtained.

  FIG. 18 shows an example of a flowchart of wavefront aberration measurement in the seventh embodiment. Differences from the first embodiment (see FIG. 4) will be mainly described. The alignment (S110) and measurement start trigger (S120) of the wavefront aberration measuring apparatus 1 are the same as those in the first embodiment. After the trigger for starting measurement (S120), corneal aberration (second wavefront aberration) is measured (S125). The measurement of corneal aberration (S125) is performed by irradiating the cornea 82 with the illumination light beam (second illumination light beam) of the anterior ocular segment illumination system (second illumination optical system) 30 and the anterior ocular segment observation system (second light reception). An optical system) 40 receives a reflected light beam from the cornea 82 by a light receiving unit (second light receiving unit) 41, transmits a received light signal (7 within ○) to the calculation unit 90, and a wavefront aberration calculation unit of the calculation unit 90 This is done by calculating wavefront aberration at 901. For example, the light source 31 uses a near-infrared wavelength of 950 nm, the reflected light from the cornea is received by the light receiving unit 41, the corneal shape is calculated from the received light signal by the wavefront aberration calculating unit 901, and then converted into wavefront aberration of each wavelength. . In the measurement of corneal aberration, for example, general values (refractive index 1.3375, Abbe number 57.1) are used for the refractive index and Abbe number of the cornea. Next, a wavefront aberration measurement loop (S130 to S150) is entered. The processing contents of this loop (S130 to S150) are the same as those in the first embodiment. In the wavefront aberration measurement (S140), the illumination light beam (first illumination light beam) of the illumination optical system (first illumination optical system) 10 is irradiated to the fundus 81 (S141), and the light reception optical system (first light reception optical system). ) 20, the reflected light beam from the fundus 81 is received by the light receiving unit 21 (first light receiving unit) (S 142), and the wavefront aberration calculating unit 901 calculates and calculates the wavefront aberration. In the wavefront aberration measurement loop (S130 to S150), the remeasurement determination unit 903 determines whether the number of wavelengths has reached a predetermined number (S150), and determines that the number of wavelengths has reached the predetermined number. Then, the internal aberration at each wavelength is calculated (S162). That is, the chromatic aberration calculator 902 obtains the wavefront aberration inside the eye by subtracting the corneal aberration (second wavefront aberration) from the cornea from the wavefront aberration (first wavefront aberration) from the fundus 81 at each wavelength. . Then, the chromatic aberration in the eye is obtained from the change of the wavefront aberration in the eye depending on the wavelength (S164). Thereby, it is possible to measure the chromatic aberration inside the eye excluding the influence of the curvature of the cornea. Here, an example in which the light source unit 11 of the illumination light source system 10 uses two light sources has been described. However, it is also possible to obtain chromatic aberration in the eye at a number of wavelengths by using a number of light sources and wavelength tunable lasers. is there.

[Measurement of corneal aberration]
Next, corneal aberration measurement will be described. The calculation unit 90 acquires the anterior segment image (with the placido ring 31) and stores it in the storage unit 94. The calculation unit 90 performs image processing on the anterior segment image in the wavefront aberration calculation unit 901 to detect platid rings and pupil edges. Next, the corneal shape is calculated based on the detected data. Next, a corneal aberration (second wavefront aberration) is calculated from the calculated corneal shape. Here, the calculation result is obtained as a Zernike coefficient.

Details of corneal aberration measurement will be described below. First, an anterior segment image is acquired.
FIG. 19 is a diagram for explaining the temporal change of the cornea shape. FIG. 19 (a) is immediately after the start of measurement, and when analyzed, the corneal wavefront aberration is relatively small. On the other hand, FIG. 19B is a graph in which 30 seconds have elapsed from the start of measurement. The platid ring image is blurred, and the corneal wavefront aberration is relatively large when analyzed.

  FIG. 20 is a diagram for explaining a temporal change in blurring of the placido ring image. FIG. 20A is immediately after the start of measurement, and as shown by the arrows, the reflected image is clear and the width of the reflected image of the placido ring is narrow. On the other hand, FIG. 20B is a graph in which a predetermined time has elapsed from the start of measurement, and as shown by an arrow, the reflected image is blurred and the width of the reflected image of the placido ring is wide.

  Next, the wavefront aberration calculator 901 performs image processing. Based on the acquired anterior segment image, a straight line passing through the bright spot at the apex of the cornea in FIG. 19 is selected, and an intensity profile on the straight line as shown in FIG. 20 is obtained. Based on the profile, a peak in both directions (corresponding to a placido ring image) is detected from the corneal apex. Further, as a method of spreading the intensity around the peak, the half width of the peak to which the peak belongs is obtained. Further, the next peak is detected toward the edge. Next, a straight line passing through the corneal apex is sequentially changed to select a straight line (for example, the first straight line is 0 degree, up to 170 degrees every 10 degrees), and the peak detection is repeated until one round is completed. Thereafter, the wavefront aberration calculator 901 stores the data at each evaluation point in the storage unit 94 for time series comparison. In the corneal shape data thus obtained, for example, the peak value or the coordinate value of the center of gravity (ring position) and the intensity and / or half-value width are stored in time series for each ring and angle.

Next, a method for calculating the corneal shape will be described. As an example, the measurement method of the corneal shape is based on Rand RH, Howland HC, Applet RA “Mathical model of a 9 encipher disco karatometer and its implications for recovery.” explain.
Assume that the corneal shape is expressed by the following function.
Z _c = f (x, y)
Here, x and y are coordinates on the cornea.

A light beam from a certain placido ring 31 forms an image at a certain point of the image sensor. The position of the placido ring 31 is (x _s , y _s ), and the corresponding point on the image sensor of the light receiving unit 41 and the point on the conjugate cornea 82 are (x, y) (see FIG. 1). If the distance from the placido ring 31 to the reference plane (zero position) of the function of the cornea 82 is Z _s , these relationships are expressed by the following two sets of equations.
Here, Z _s can be controlled by the working distance adjusting unit 50 or an accurate distance value can be obtained. Incidentally, _{f x} is the partial derivative of x of the function f, _{f y} represents the partial derivative of y.

Here, since the platide ring 31 is circular, it is rotationally symmetric with respect to the central axis of the anterior segment illumination system 30.
Let this Constant (a constant value) be represented by r _s (note that this is known because it is a device value). Then, since the ring to which the position of the point on the image sensor to be measured belongs can be known at the stage of image processing by the calculation unit 90, the (coordinate of point coordinates on the image element) pair (the radius of the ring) If the relationship is digitized, for example, on 11 rings and 360 points on each ring, a data pair having a relationship corresponding to the digit can be obtained.

Here, the Zernike polynomial expansion is adopted as a function. In the normal cornea 82, since it may be considered that there is no very high-order shape change, if the analysis diameter is about 6 mm, the development is terminated in the sixth order,
It is possible to express it. Here, r _n is the radius to be analyzed, is used for normalization.
If this Zernike expansion is put into the above two relational expressions and the fact that the placido ring is rotationally symmetric, the coefficient c _i ^j can be determined by using the nonlinear least square method. If the coefficient determined in this way is substituted again in the Zernike expansion, the function f (x, y) is determined, and the corneal shape is obtained.

  Next, corneal aberration (corneal wavefront aberration, second wavefront aberration) is calculated. Since a corneal shape has been obtained, it is well known that corneal wavefront aberrations that are strictly geometrically optical can be obtained from ray tracing of an aspheric surface, which is known in optical design. Here, as an example, a method for obtaining the corneal wavefront aberration very simply will be introduced. For example, in the case of corneal wavefront aberration with a diameter of 6 mm on the cornea, the corneal shape is approximated to a sphericity (referred to as a reference spherical surface), and the difference between the actual corneal shape and the reference spherical shape is taken. By applying the refractive index (n−1), the corneal wavefront aberration can be obtained from the corneal shape. However, since the spherical aberration also occurs from the original reference spherical surface, this is added. As a result, it is possible to obtain corresponding points on the image sensor of the light receiving unit 41 within an approximate accuracy of 5%.

[Eighth Embodiment]
In the eighth embodiment, an example of correcting wavefront aberration using a model eye will be described. Using a model eye that reflects a reflected light beam that does not cause chromatic aberration, or a refractive model eye that has been corrected for chromatic aberration in advance, the wavefront aberration inside the device is obtained, and the wavefront aberration inside the device is determined from the wavefront aberration measured by the eye to be examined. Is subtracted to correct the wavefront aberration. Here, the range in which chromatic aberration is practically negligible includes that chromatic aberration does not occur.

  FIG. 21 shows a configuration example of the electric system in the eighth embodiment. The storage unit 94 includes a correction data storage unit 941 that stores data when wavefront aberration is measured using the model eye 85 as wavefront aberration inside the apparatus. Further, the chromatic aberration calculator 902 performs wavefront aberration correction calculation using the wavefront aberration inside the apparatus stored in the correction data storage unit 941. Other configurations are the same as those of the first embodiment.

  FIG. 22 shows a configuration example of the model eye 85. The model eye 85 includes an opening 851, a first mirror 852, a second mirror 853, and a diffusion plate 854. The opening 851 is for entering the illumination light beam (spot light) from the illumination optical system 10 and emitting the reflected light beam to the light receiving optical system 20. The illumination light beam is reflected by the first mirror 852 and the second mirror 853 and enters the diffusion plate 854. In addition, the diffused light beam reflected by the diffusion plate 854 is reflected by the second mirror 853 and the first mirror 852 and is emitted from the opening 851. There are multiple model eyes, and the emitted light beam is parallel light (0 diopter), convergent light (negative diopter), divergent light (positive diopter) according to the spherical component of each model eye. Or The first mirror 852 and the second mirror 853 are formed in a spherical shape, a toric surface, or the like so that the reflected light beam is a light beam having no aberration or little aberration. Further, the first mirror 852 is provided with a stop 855 around the periphery so that the reflected light beam becomes a light beam having a predetermined diameter. By configuring the model eye 85 in this way, it is possible to emit a reflected light beam with little or no chromatic aberration. In the case of a refractive model eye with little chromatic aberration, correction data is created and stored in the correction data storage unit 941 so that chromatic aberration can be corrected in advance.

  FIG. 23 shows an example of a flowchart for creating correction data in the eighth embodiment. Before the wavefront aberration measurement flow (see FIG. 4) in the first embodiment, a correction data creation flow is performed. This processing flow may be performed once for each model eye. First, the model eye is fixed (S210). It is fixed with a hardware or the like so that the optical axis of the model eye 85 is aligned with the optical axis of the wavefront aberration measuring apparatus 1. Next, the wavelength selection unit 904 of the calculation unit 90 sets the wavelength of the illumination light beam from the light source unit 11 of the illumination optical system 10 (S230). The processing loop for setting the wavelength of the illumination light beam (S230), measuring the wavefront aberration (S240), and determining whether the number of wavelengths has reached a predetermined number (S250) is a flow of wavefront aberration measurement in the first embodiment. This is the same as the processing loop for setting the wavelength of the illumination light beam (S130), measuring the wavefront aberration (S140), and determining whether the number of wavelengths has reached a predetermined number (S150) (see FIG. 4). However, in the correction data creation flow, it is preferable to set many wavelengths finely so that they can be applied to the measurement of wavefront aberrations at many wavelengths. If the re-measurement determination unit 903 determines that the number of wavelengths has reached a predetermined number, correction data is created (S260). That is, data when wavefront aberration is measured using the model eye 85 is stored in the correction data storage unit 941 as wavefront aberration inside the apparatus. The subsequent processing flow of wavefront aberration measurement is substantially the same as in the first embodiment (see FIG. 4). However, in the chromatic aberration analysis 160, the wavefront aberration is corrected by subtracting the wavefront aberration in the apparatus stored in the correction data storage unit 941 from the wavefront aberration measured by the eye 80 to be examined. Thereby, the correction process which subtracts the chromatic aberration of the wave front inside an apparatus can be performed.

[Ninth Embodiment]
In the ninth embodiment, an example in which continuous measurement is performed while adjusting the position of the fixation target 72 will be described. By using the fixation target 72 in the fixation optical system 70, the line of sight of the eye 80 to be examined is stabilized. Further, by adjusting the position of the fixation target 72, the position of the focal point of the eye 80 to be examined looking at the fixation target 72 can be changed. Therefore, by changing the position of the fixation target 72, a change in chromatic aberration due to a change in the focus position of the eye to be examined can be measured.

FIG. 24 shows an example of a flowchart of wavefront aberration measurement in the ninth embodiment. Differences from the first embodiment will be mainly described. Wavefront aberration measurement from the alignment (S110) of the wavefront aberration measuring apparatus 1, the trigger for starting measurement (S120), the setting of the wavelength of the illumination light beam (S130) to the determination whether the number of wavelengths has reached a predetermined number (S150) The measurement loop is the same as in the first embodiment. Next to the alignment (S110) of the wavefront aberration measuring apparatus 1, how to adjust the fixation target 72 is set. For example, an adjustment amount 5D (a range in which the position of the fixation target 72 in the optical axis direction is changed) and a change amount 1D (a width in which the position of the fixation target 72 in the optical axis direction is changed) are set (S112). The adjustment amount 5D and the change amount 1D are stored in the storage unit 94. Here, the adjustment amount 5D is set to 5 times the change amount 1D. Next, the position of the fixation target 72 in the optical axis direction is selected from the set range, and the fixation target 72 is set at the initial position (S114). Next, a trigger is made to start measurement (S120). In the wavefront aberration measurement loop (S130 to S150), when the re-measurement determination unit 903 determines that the number of wavelengths has reached a predetermined number, the calculation unit 90 uses a fixation target position setting unit (not shown). Then, it is determined whether or not the change in the position of the fixation target 72 in the optical axis direction has reached the adjustment amount (S155). When the fixation target position setting unit determines that the change in the position of the fixation target 72 in the optical axis direction has not reached the adjustment amount, for example, a waiting time of 1 second is taken ( S157 ), and the position of the fixation target 72 is determined. Is changed by 1D ( S158 ), and the process returns to the setting of the wavelength of the illumination light beam of the loop for measuring the wavefront aberration (S130). That is, the wavefront aberration is measured for each wavelength by changing the position of the fixation target 72. When the fixation target position setting unit determines that the change in the position of the fixation target 72 in the optical axis direction has reached the adjustment amount, that is, when the measurement of the fixation target 72 is changed six times, the chromatic aberration is determined. The calculation unit 902 analyzes the chromatic aberration of the wavefront (S160). The analysis of chromatic aberration is the same as in the first embodiment, but the chromatic aberration when the position of the fixation target 72 is adjusted is obtained. Further, the change of the position of the fixation target 72 and the change of the wavelength of the light source of the illumination optical system 10 can be executed by a program process, and in this case, continuous measurement is possible. Thereby, the chromatic aberration matched to the line of sight of the eye to be injured is obtained.

[Tenth embodiment]
In the fifth embodiment, an example has been described in which the setting is performed twice or more and the wavelength to be used is added or changed. Set and measure, then determine if the near-infrared wavelength measurement is sufficient or inadequate and the wavefront aberration should be measured at the visible wavelength. When it is determined that measurement is to be performed, an example will be described in which the next setting is performed by setting the wavelength in the visible range. That is, in the present embodiment, the first setting is limited to the near infrared wavelength, and the second setting is limited to the visible wavelength. In addition, the second setting may not be performed. In the fifth embodiment, an example in which chromatic aberration is measured has been described. In the tenth embodiment, an example in which chromatic aberration is not measured will be described. Differences from the fifth embodiment (or the first embodiment via the fifth embodiment) will be mainly described.

  Conventionally, measurement of wavefront aberration was desired to be performed with visible light, but since the eye to be measured felt dazzling, it was measured with a single color of infrared light. Further, the measurement of the chromatic aberration of the wavefront, that is, the change in the amount of aberration for each wavelength has not been made. However, in the case of cataracts, the wavefront aberration in the visible range may not be estimated from the measurement of infrared light. In recent years, IOLs (Intraocular Lenses) and contact lenses have become widespread, and multifocal IOLs such as near vision and far vision are also used. These multifocal IOLs have significantly different wavefront aberrations and chromatic aberrations from the naked eye, and are visible. Wavefront aberration cannot be estimated from the measurement of infrared light. In particular, in a diffraction type IOL, an accurate diffraction effect cannot be measured by measurement with infrared light by objective refraction measurement. For this reason, it is necessary to measure the wavefront aberration in the visible range.

  FIG. 25 shows a configuration example of the electric system in the tenth embodiment. The configuration of the optical system is the same as that of the fifth embodiment (that is, the first embodiment, see FIG. 1). In the configuration of the electric system, a measurement result selection unit 906 is added and a chromatic aberration calculation unit 902 is deleted in the calculation unit 90 as compared to the fifth embodiment (that is, the first embodiment, see FIG. 3). Yes. Further, in the fifth embodiment, the remeasurement determination unit 903 determines whether the measurement at the wavelength of the previous measurement is sufficient or insufficient, and whether the next measurement should be performed by adding or changing the wavelength. In contrast to this, in the present embodiment, it is determined whether measurement at the near-infrared wavelength is sufficient or insufficient, and whether the wavefront aberration should be measured at the visible wavelength. In addition, when the remeasurement determination unit 903 determines that the measurement at the near infrared wavelength is sufficient, the measurement result selection unit 906 acquires the wavefront aberration at the near infrared wavelength as the measurement result, When it is determined that the measurement is performed at the visible wavelength, the wavefront aberration at the visible wavelength is acquired as the measurement result. Other configurations are the same as those of the fifth embodiment (that is, the first embodiment).

  FIG. 26 shows an example of a flowchart of wavefront aberration measurement in the tenth embodiment. The alignment (S110) and the measurement start trigger (S120) of the wavefront aberration measuring apparatus 1 are the same as those in the first embodiment. The loop for measuring the wavefront aberration in the near infrared region from the setting of the wavelength of the illumination light beam (S330) to the determination of whether or not the number of wavelengths has reached a predetermined number (S350) has a set wavelength in the near infrared region. Except for the point limited to the wavelength (here, 840 nm), it is the same as the first embodiment. In the loop (S330 to S350) for measuring the wavefront aberration in the near infrared region, the wavefront aberration measurement (S340) is as follows. First, the illumination optical system 10 irradiates the fundus 81 of the eye 80 with the illumination light beam emitted from the light source unit 11 as spot light (S341). Next, in the light receiving optical system 20, the reflected light beam from the fundus 81 is divided into a plurality of divided light beams by the Hartmann plate, and the plurality of divided light beams are received by the light receiving unit 21 (S342). The light receiving unit 21 transmits a light reception signal (4 in a circle) to the calculation unit 90. Next, in the calculation unit 90, the wavefront aberration calculation unit 901 calculates wavefront aberration for light having a wavelength in the near infrared region received by the light receiving unit 21 (S343). If the re-measurement determination unit 903 determines that the number of wavelengths has reached a predetermined number, the re-measurement determination unit 903 then determines whether the measurement at the near-infrared wavelength is sufficient or insufficient, and the visible region. It is determined whether the wavefront aberration should be measured at the wavelength (S400).

  As a criterion for determining whether wavefront aberration should be measured at a wavelength in the visible range, for example, when a spot of received light is separated into a plurality of spots, that is, there are two spot light peak values in a local region. If the spot is blurred or the spot is blurred, it is determined to measure again. Further, when the spherical aberration is larger than a predetermined value (for example, 0.5 when the diameter of the pupil to be analyzed is 6 mm), it is determined to remeasure. If it is determined that the measurement in the near-infrared wavelength is sufficient, the measurement result selection unit 906 acquires the analysis result of the wavefront aberration in the near-infrared region and displays it on the display unit 93 (S480). When it is determined that the wavefront aberration is measured at the visible wavelength, the loop (S430 to S450) for measuring the wavefront aberration in the visible region is entered. The wavefront aberration measurement loop from the setting of the wavelength of the illumination light beam (S430) to the determination of whether or not the number of wavelengths has reached a predetermined number (S450) has a set wavelength of visible wavelength (here, 560 nm). Except for the point that is limited to (Yes), it is the same as the first embodiment. In the measurement loop (S430 to S450) of the wavefront aberration in the visible region, the wavefront aberration measurement (S440) is as follows. First, the illumination optical system 10 irradiates the fundus 81 of the eye 80 to be examined with the illumination light beam emitted from the light source unit 11 as spot light (S441). Next, in the light receiving optical system 20, the reflected light beam from the fundus 81 is divided into a plurality of divided light beams by the Hartmann plate, and the plurality of divided light beams are received by the light receiving unit 21 (S442). The light receiving unit 21 transmits a light reception signal (4 in a circle) to the calculation unit 90. Next, in the calculation unit 90, the wavefront aberration calculation unit 901 calculates wavefront aberration for light having a wavelength in the near infrared region received by the light receiving unit 21 (S443). However, if it is determined in the determination that the wavefront aberration should be measured at a wavelength in the visible range (S400) that there are two spot light peak values in the local region, only the peak with the higher peak is used. Is used for wavefront aberration analysis, or wavefront aberration analysis is performed for two groups of only one having a higher peak and one having a lower peak. When the re-measurement determination unit 903 determines that the number of wavelengths has reached a predetermined number, the measurement result selection unit 906 acquires the analysis result of the wavefront aberration in the visible range and displays it on the display unit 93 (S480). .

FIG. 27 shows an example of imaging on the light receiving surface of the light receiving unit 21 of the light receiving optical system 20. In the example of FIG. 27 (a) is eye almost no aberration, the measurement of the near-infrared (wavelength 840 nm), a wide range in the spot light is observed in a lattice shape and uniform, spherical aberration Zernike coefficients c ₄ ⁰ 0. As small as 015. FIG. 27B shows an example of a model eye using a refractive IOL. In the near-infrared (wavelength 840 nm) measurement, the spot light changes concentrically due to wavefront aberration, and the Zernike coefficient c ₄ ⁰ is relatively large as 0.75. FIG. 27C shows an example of an eye using a diffractive IOL. In the measurement of visible light (wavelength 690 nm), the spot light is separated. In the near-infrared (wavelength 840 nm) measurement, no separation was observed, resulting in blurring.
As described above, according to the present embodiment, it is possible to determine whether or not the measurement of the wavefront aberration is sufficient in the near-infrared region, and to provide a device and a method capable of performing the measurement in the visible region when insufficient. be able to.

[Eleventh embodiment]
In the tenth embodiment, the light source unit 11 of the illumination optical system 10 has been described as using a total of two light sources, one light source that emits light in the near infrared region and one light source that emits light in the visible region. However, in the eleventh embodiment, the light source unit 11 of the illumination optical system 10 has a total of four light sources, one light source that emits light in the near infrared region and three light sources that emit light having different wavelengths in the visible region. An example will be described in which measurement is performed by switching between these. Differences from the tenth embodiment will be mainly described. Regarding the configuration of the optical system (see FIG. 1), LEDs that emit red, green, and blue light can be used as three light sources that emit visible light. Lights from four light sources are incident on four fibers, respectively, and the optical path is switched using a four-branch coupler as a tree-type fiber coupler, and the light is emitted from the exit end of one fiber. In the wavefront aberration measurement flowchart (see FIG. 26), in the visible wavelength setting step (S330), the wavelength selector 904 sets the three wavelengths used for measurement and the order in which the measurement is performed (a predetermined number is also set). The wavelength used for measurement is selected in the set order. Other configurations and processing flow are the same as those in the tenth embodiment, and it is determined whether or not the measurement of the wavefront aberration is sufficient in the near-infrared region. If the measurement is insufficient, the measurement in the visible region can be performed. Apparatus and method can be provided. .

[Twelfth embodiment]
In the twelfth embodiment, an example of Fourier transform of a Hartmann image will be described as an example of chromatic aberration analysis and optical characteristic analysis in the tenth embodiment.

  FIG. 28 shows a configuration example of the electrical system in the twelfth embodiment. Compared to the tenth embodiment (see FIG. 25), a chromatic aberration calculator 902 and an optical characteristic analyzer 905 are added. The chromatic aberration calculator 902 and the optical characteristic analyzer 905 are the same as those in the first embodiment. However, in the present embodiment, Fourier transform is performed on the Hartmann image as the optical characteristic analysis.

  FIG. 29 shows an example of a flowchart of wavefront aberration measurement in the twelfth embodiment. The steps from the alignment (S110) of the aberration measuring apparatus 1 to the wavefront aberration measurement loop (S430 to S450) in the visible range are the same as those in the tenth embodiment. Next, the chromatic aberration calculation unit 902 analyzes chromatic aberration (S460). For example, when the diffractive IOL is used in the eye 80 to be examined, the chromatic aberration is greatly different from the normal eye data or the sign appears in reverse, so that the diffractive IOL is easy to find. Next, the optical characteristic analysis unit 905 performs Fourier transform of the Hartmann image (S470). After the Fourier transform of the Hartmann image, the measurement result selection unit 905 acquires the analysis result of the wavefront aberration in the visible range and displays it on the display unit 93 (S480). Optical characteristic analysis other than the Fourier transform of the Hartmann image is also possible.

  FIG. 30 shows an example of Fourier transform of a Hartmann image. FIG. 30A shows a case where the spot light is one point, and FIG. 30B shows a case where the spot light is separated into two points. The horizontal axis represents frequency and the vertical axis represents light intensity, which corresponds to equivalent sphericity. Therefore, it is possible to calculate the equivalent sphericity. In FIG. 30A, there is one spot light. In FIG. 30 (b), it is separated into two points corresponding to near vision and far vision. For this reason, it is possible to calculate the equivalent sphericity of both near vision and far vision at one degree.

[Thirteenth embodiment]
In the above embodiment, the wavefront aberration measuring apparatus has been described. In this embodiment, an eye optical characteristic measuring apparatus that is a superordinate concept of the wavefront aberration measuring apparatus will be described. That is, for the wavefront aberration measuring apparatus in the twelfth embodiment, based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculator, the optical characteristics of the eye to be examined (wavefront aberration, refractive index, PSF, MTF, visual acuity, If an optical characteristic analysis unit 905 that calculates (contrast sensitivity, etc.) is provided, it can be said to be an eye optical characteristic measurement device. That is, it has a light source unit that emits light of a plurality of wavelengths including at least a visible region and a near-infrared region and switches and emits light of a plurality of wavelengths, and the illumination light beam emitted from the light source unit is used as spot light of the eye to be examined A light receiving optical system having an illumination optical system that irradiates the fundus, a Hartmann plate that divides a reflected light beam from the fundus into a plurality of divided light beams, and a light receiving unit that receives the plurality of divided light beams divided by the Hartmann plate; A wavefront aberration calculator for calculating the wavefront aberration of light of each wavelength received by the optical unit, and an optical characteristic for calculating the optical characteristics of the eye based on the wavefront aberration at each wavelength determined by the wavefront aberration calculator It can function as an eye optical characteristic measuring device provided with a calculating part. Thereby, the wavelength suitable for the measurement can be selected and the optical characteristics of the eye to be examined can be measured.

  The present invention can also be realized as a program for causing a computer to execute the wavefront aberration measuring method described in the flowcharts and the like of the above embodiments. The program may be used by being stored in an internal storage unit of the computer, may be used by being stored in an external storage device, or may be used by downloading from the Internet. Moreover, it is realizable also as a recording medium which recorded the said program.

  Although the embodiment of the present invention has been described above, the embodiment is not limited to the above example, and it is obvious that various modifications can be made without departing from the spirit of the present invention.

For example, the aspects described in the above embodiments can be combined with each other. For example, in the second to sixth embodiments or the tenth to twelfth embodiments, the chromatic aberration measurement in the eye of the seventh embodiment, the correction of the wavefront aberration of the eighth embodiment, the ninth You may combine the adjustment of the eyes | visual_axis using the fixation target of embodiment, etc. A plurality of (2 or more, 3 or more) embodiments may be combined. In addition, a chromatic aberration calculator 902 and an optical characteristic analyzer 905 may be added to the tenth and eleventh embodiments. Also, the configuration of the optical system and the electrical system can be changed, for example, by changing the positions of the illumination optical system 10 and the light receiving optical system 20. In addition, for some flowcharts of wavefront aberration measurement (FIG. 4, FIG. 14, etc.), the order of steps may be changed as appropriate, such as analyzing chromatic aberration immediately after the wavefront aberration measurement. Further, (see FIG. 12) Fourth Embodiment (see Fig. 14) Fifth Embodiment In the ninth embodiment (see FIG. 24), the remeasurement judging unit 903 respectively two determination However, the role may be shared by the first remeasurement determination unit and the second remeasurement determination unit. In the above embodiment, the wavelength (560 nm) close to the d-line is used as the reference wavelength for chromatic aberration, but d-line, e-line, F-line, and C-line may be used. Further, a dichroic mirror and a wavelength selective mirror may be used as a beam splitter, or a beam splitter using birefringence may be used. Further, the number of split light beams by the Hartmann plate, the measurement wavelength, the number of wavelengths used for measurement (predetermined number), and the like can be arbitrarily set, and the arrangement, characteristics, and the like of the optical device can be changed.

  The present invention is used for measuring the wavefront aberration of light reflected from the eye.

It is a figure which shows the structural example of the optical system of the wavefront aberration measuring apparatus in 1st Embodiment. It is a figure which shows the example of the filter characteristic of a beam splitter (wavelength selective mirror). It is a figure which shows the structural example of the electric system of the wavefront aberration measuring apparatus in 1st Embodiment. It is a figure which shows the example of the flowchart of the wavefront aberration measurement in 1st Embodiment. It is a table | surface which shows the Zernike coefficient of the (x, y) coordinate in wavelength 560nm and wavelength 840nm. It is a figure which shows the example of a measurement of the wavefront aberration in wavelength 560nm and wavelength 840nm. It is a figure which shows the example of white PSF. It is a figure which shows the example of a visual acuity simulation image It is a figure which shows the example of the band pass characteristic of a liquid crystal wavelength variable filter. It is a figure which shows the structural example of a liquid crystal wavelength variable filter. It is a figure which shows the example of the wavelength selection method of a liquid crystal wavelength variable filter. It is a figure which shows the example of the flowchart of the wavefront aberration measurement in 4th Embodiment. It is a figure which shows the example of the timing of the control signal in the case of measuring repeatedly and continuously. It is a figure which shows the example of the flowchart of the wavefront aberration measurement in 5th Embodiment. It is a figure which shows the example which graphed the spherical aberration in each incident position on a pupil for every wavelength. It is a figure for demonstrating determination of the grade of a blur. It is a figure which shows the example of the chromatic aberration graph of each Zernike coefficient at the time of measuring with multiple wavelengths. It is a figure which shows the example of the flowchart of the wave aberration measurement in 7th Embodiment. It is a figure explaining the time change of a cornea shape. It is a figure explaining the time change of the blur of a placido ring image. It is a figure which shows the structural example of the electric system in 8th Embodiment. It is a figure which shows the structural example of a model eye. It is a figure which shows the example of the flowchart of correction data creation. It is a figure which shows the example of the flowchart of the wave aberration measurement in 9th Embodiment. It is a figure which shows the structural example of the electric system of the wavefront aberration measuring apparatus in 10th Embodiment. It is a figure which shows the example of the flowchart of a wavefront aberration measurement in 10th Embodiment. 2 is a diagram illustrating an example of imaging on a light receiving surface of a light receiving unit 21 of a light receiving optical system 20. It is a figure which shows the structural example of the electric system in 12th Embodiment. It is a figure which shows the example of the flowchart of the wavefront aberration measurement in 12th Embodiment. It is a figure which shows the example of the Fourier transform of a Hartmann image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wavefront aberration measuring apparatus 10 Illumination optical system 11 Light source part 13 Fiber coupler 15 Optical system moving means 20 Light reception optical system 21 Light reception part 22 Hartmann plate 30 Anterior eye part illumination system 31 Ring-shaped light source 40 Anterior eye part observation system 41 Light reception part 42 Telecentric stop 50 First adjustment optical system 51 Light source unit 52 Light receiving unit 60 Second adjustment optical system 61 Light source unit for alignment 70 Fixation optical system 71 Light source unit 72 Fixation target 80 Eye to be examined 81 Retina (fundus)
82 Cornea (Anterior Eye)
83 Crystal 85 Model eye 90 Calculation unit 91 Control unit 92 Input unit 93 Display unit 94 Storage unit 95 First drive unit 96 Second drive unit 101, 103, 107 Condensing lens 102 Aperture 104, 106 Beam splitter 105 Beam splitter (Wavelength selective mirror)
108 Rotary prism 111, 112 Light source 121-123 Fiber 201, 203, 205 Condensing lens 202 Aperture 204 Reflecting plate 401-403 Condensing lens 404 Beam splitter 501, 502 Condensing lens 601 Condensing lens 701 Condensing lens 702 Reflecting plate 851 Aperture 852 First mirror 853 Second mirror 854 Diffuser 855 Diaphragm 901 Wavefront aberration calculator 902 Chromatic aberration calculator 903 Remeasurement determination unit 904 Wavelength selection unit 905 Optical characteristic analysis unit 906 Measurement result selection unit 941 Correction data storage In part ○, 1 in wavelength selection signal ○ 3 in movement control signal ○ 4, 7, 10 in light reception signal ○ 5, 6, 9, 11 in light reception signal ○ 8 in control signal ○ rotation control signal c _i ^{2j -i} Zernike coefficients (x, y) on the cornea coordinates _{(x s, y} s) placido ring position Z Distance from the Placido disk to the reference surface of the function of the cornea

Claims (13)

An illumination optical system that has a light source unit that switches and emits light of a plurality of wavelengths, and irradiates the fundus of the eye to be examined with the illumination light beam emitted from the light source unit as spot light;
A light receiving optical system having a Hartmann plate that divides the reflected light beam from the fundus into a plurality of divided light beams, and a light receiving unit that receives the plurality of divided light beams divided by the Hartmann plate;
A wavefront aberration calculating unit for calculating wavefront aberration for each wavelength of light received by the light receiving unit;
And a chromatic aberration calculation section for obtaining the chromatic aberration of the wavefront based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculating unit;
A re-measurement determination unit that determines whether the measurement at the wavelength of the previous measurement is sufficient or not sufficient for the measurement of the wavefront aberration, and determines whether the next measurement should be performed by adding or changing the wavelength;
A wavelength selection unit that selects the wavelength to be added or changed when the re-measurement determination unit determines that the next measurement is to be performed;
The re-measurement determination unit determines whether the next measurement should be performed based on a separation state or a blur state of received light on the light receiving surface of the light receiving unit, and the wavelength selection unit receives light from the light receiving unit. Selecting one or a plurality of wavelengths to be added or changed in the next measurement based on the separation state or blurring state of the received light on the surface;
Wavefront aberration measuring device. An illumination optical system that has a light source unit that switches and emits light of a plurality of wavelengths, and irradiates the fundus of the eye to be examined with the illumination light beam emitted from the light source unit as spot light;
A light receiving optical system having a Hartmann plate that divides the reflected light beam from the fundus into a plurality of divided light beams, and a light receiving unit that receives the plurality of divided light beams divided by the Hartmann plate;
A wavefront aberration calculating unit for calculating wavefront aberration for each wavelength of light received by the light receiving unit;
And a chromatic aberration calculation section for obtaining the chromatic aberration of the wavefront based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculating unit;
A re-measurement determination unit that determines whether the measurement at the wavelength of the previous measurement is sufficient or not sufficient for the measurement of the wavefront aberration, and determines whether the next measurement should be performed by adding or changing the wavelength;
A wavelength selection unit that selects the wavelength to be added or changed when the re-measurement determination unit determines that the next measurement is to be performed;
The re-measurement determination unit determines whether to perform the next measurement based on a change of the wavefront aberration obtained by the wavefront aberration calculation unit according to a wavelength;
The wavelength selection unit selects one or a plurality of wavelengths to be added or changed in the next measurement based on the change of the wavefront aberration obtained by the wavefront aberration calculation unit according to the wavelength;
Wavefront aberration measuring device. The plurality of wavelengths includes at least a near-infrared wavelength and a visible wavelength;
The wavefront aberration measuring apparatus according to claim 1 or 2 . The wavelength selection unit sequentially selects from long wavelengths when selecting the wavelength to be added or changed;
The wavefront aberration measuring apparatus according to any one of claims 1 to 3 . The wavelength selection unit sets the wavelength to be added or changed at a coarse wavelength interval where the change due to the wavelength of the wavefront aberration obtained in the previous measurement is small, and at a fine wavelength interval where the change due to the wavelength of the wavefront aberration is large. select;
The wavefront aberration measuring apparatus according to claim 2 . The light source unit combines a plurality of light sources that emit light of different wavelengths, a plurality of fibers that allow light incident from the incident end to pass through and exit from the output end, and light incident from the two fibers. One or a plurality of fiber couplers that emit to one fiber, and the plurality of fibers and the one or more fiber couplers are connected in a tree shape, and light having different wavelengths emitted from the plurality of light sources is emitted. The light is input from the input end of a different fiber, and is configured to select light of one wavelength emitted from any one light source and output from the output end of one fiber;
The wavefront aberration measuring apparatus according to any one of claims 1 to 5 . Using the model eye that reflects a reflected light beam that does not cause chromatic aberration or has been corrected in advance as the eye to be examined, data when wavefront aberration is measured at each wavelength is stored as wavefront aberration inside the apparatus. A correction data storage unit to be stored;
The chromatic aberration calculating unit removes the wavefront aberration inside the device at each wavelength stored in the correction data storage unit from the wavefront aberration of each wavelength obtained by the wavefront aberration calculating unit, thereby Determine the chromatic aberration of the wavefront;
The wavefront aberration measuring apparatus according to any one of claims 1 to 6 . An illumination optical system that has a light source unit that switches and emits light of a plurality of wavelengths, and irradiates the fundus of the eye to be examined with the illumination light beam emitted from the light source unit as spot light;
A light receiving optical system having a Hartmann plate that divides the reflected light beam from the fundus into a plurality of divided light beams, and a light receiving unit that receives the plurality of divided light beams divided by the Hartmann plate;
A wavefront aberration calculating unit for calculating wavefront aberration for each wavelength of light received by the light receiving unit;
And a chromatic aberration calculation section for obtaining the chromatic aberration of the wavefront based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculating unit;
Using the model eye that reflects a reflected light beam that does not cause chromatic aberration or has been corrected in advance as the eye to be examined, data when wavefront aberration is measured at each wavelength is stored as wavefront aberration inside the apparatus. A correction data storage unit to be stored;
The chromatic aberration calculating unit removes the wavefront aberration inside the device at each wavelength stored in the correction data storage unit from the wavefront aberration of each wavelength obtained by the wavefront aberration calculating unit, thereby Determine the chromatic aberration of the wavefront;
Wavefront aberration measuring device. Predetermining the order of wavelengths of light emitted from the light source unit, and switching automatically and continuously;
The wavefront aberration measuring apparatus according to claim 1. A fixation optical system for irradiating the eye to be examined with a fixation light beam having a wavelength in the visible range in order to stabilize the line of sight of the eye to be examined with a fixation target;
The fixation target is adjustable in position in the optical axis direction of the fixation optical system;
The wavefront aberration calculating unit obtains a spherical component for each wavelength of light received by the light receiving unit;
The chromatic aberration calculating unit obtains chromatic aberration of a wavefront from the eye to be examined in an adjustment state of the position of the fixation target based on a change of the spherical component with respect to a wavelength;
The wavefront aberration measuring apparatus according to any one of claims 1 to 9. An illumination optical system that has a light source unit that switches and emits light of a plurality of wavelengths, and irradiates the fundus of the eye to be examined with the illumination light beam emitted from the light source unit as spot light;
A light receiving optical system having a Hartmann plate that divides the reflected light beam from the fundus into a plurality of divided light beams, and a light receiving unit that receives the plurality of divided light beams divided by the Hartmann plate;
A wavefront aberration calculating unit for calculating wavefront aberration for each wavelength of light received by the light receiving unit;
And a chromatic aberration calculation section for obtaining the chromatic aberration of the wavefront based on the wavefront aberration at each wavelength obtained by the wavefront aberration calculating unit;
A fixation optical system for irradiating the eye to be examined with a fixation light beam having a wavelength in the visible range in order to stabilize the line of sight of the eye to be examined with a fixation target;
The fixation target is adjustable in position in the optical axis direction of the fixation optical system;
The wavefront aberration calculating unit obtains a spherical component for each wavelength of light received by the light receiving unit;
The chromatic aberration calculating unit obtains chromatic aberration of a wavefront from the eye to be examined in an adjustment state of the position of the fixation target based on a change of the spherical component with respect to a wavelength;
Wavefront aberration measuring device. A first illumination optical system that has a light source unit that switches and emits light of a plurality of wavelengths, and irradiates the fundus of the eye to be examined with the first illumination light beam emitted from the light source unit as spot light;
A first light receiving optical system having a Hartmann plate that divides the reflected light beam from the fundus into a plurality of divided light beams, and a first light receiving unit that receives the plurality of divided light beams divided by the Hartmann plate;
A second illumination optical system for irradiating the surface of the cornea with a second illumination light beam;
A second light receiving optical system having a second light receiving portion for receiving a reflected light beam from the surface of the cornea;
The wavefront aberration obtained by calculating the light of each wavelength received by the first light receiving unit is defined as the first wavefront aberration, and the light of each wavelength received by the second light receiving unit is calculated and obtained. A wavefront aberration calculator that obtains a wavefront aberration inside the eye by removing the second wavefront aberration from the first wavefront aberration, wherein the wavefront aberration is a second wavefront aberration;
A chromatic aberration calculator for determining chromatic aberration of the wavefront based on the wavefront aberration inside the eye of each wavelength;
Wavefront aberration measuring device A setting step of setting a wavelength emitted from the light source unit using a light source unit that switches and emits light of a plurality of wavelengths;
An illumination step of irradiating the fundus of the eye to be examined with the illumination light beam emitted from the light source unit as spot light;
A light receiving step of using a Hartmann plate that divides the reflected light beam from the fundus into a plurality of divided light beams, and receiving the plurality of divided light beams divided by the Hartmann plate;
A wavefront aberration calculating step for calculating wavefront aberration for each wavelength of light received in the light receiving step;
A re-measurement determination step for determining whether measurement has been performed at a predetermined number of wavelengths;
If it is determined in the remeasurement determination step that measurement has not been performed at a predetermined number of wavelengths, the setting step, the illumination step, the light receiving step, the wavefront aberration calculation step, and the remeasurement determination step are performed again. A re-measurement step;
A chromatic aberration calculation step of obtaining a chromatic aberration of a wavefront based on the wavefront aberration at each wavelength obtained in the wavefront aberration calculation step when it is determined in the remeasurement determination step that measurement has been performed at a predetermined number of wavelengths; Prepare;
Wavefront aberration measurement method.