JPS6351016B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for objectively measuring the refractive power of an eye to be examined.

In recent years, many objective automatic devices have been used as devices for measuring the refractive power of the eye to adjust eyeglasses, due to the fact that the measurement time is quick, no skill is required for measurement, and there is little difference in measurement between examiners. Although refractive power measurement devices have been proposed, even in these devices, final adjustment is usually performed using a subjective ophthalmoscope after objective measurement. Therefore, whether automatic or manual, the examiner must install two devices, one objective and one subjective, which requires more cost and space. There were flaws.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ocular refraction measurement device that can perform both objective and subjective tests with a single device, in view of the drawbacks of the conventional devices.

In order to achieve the above object, the present invention projects an optotype for measurement onto the fundus of the eye to be examined, detects the optotype image on the fundus of the eye to be examined, and provides an eye refractive power capable of obtaining refractive power information of the eye to be examined. In the measuring device, means for presenting the visual target for subjective optometry in the fixation visual target projection system that projects the visual fixation target, and the axial angle (AXIS), cylindrical refractive power (CYL), and spherical refractive power. It is characterized by the arrangement of a corrective optical system that can change the (SPH), making it possible to measure the subjective refractive power of the eye to be examined.

The details of this invention will be explained below with reference to the drawings.

FIG. 1 is an optical system layout diagram of the eye refractive power measuring device according to the present invention, in which 1 is a measurement light source having a wavelength in the infrared region, 2 and 3 are condensing lenses, and 4 is the fundus of the eye 8 to be examined. A movable spot diaphragm (measurement target, hereinafter simply referred to as a spot diaphragm) to be placed at a conjugate position; 5 and 6 are objective lenses; 7 and 9 are prisms; 10 is a mirror; 11 and 12 are relay lenses;
13 is a band-shaped corneal reflection removal mask placed at a position conjugate with the cornea of the eye 8 to be examined; 14 is a movable lens that moves together with the spot diaphragm 4; and 15 is an imaging lens. 16 indicates a light receiving element for measurement;
The measurement light source 1 and the corneal reflection removal mask 13
It is designed to rotate around the optical axis in synchronization with the A first relay lens 17 is movable on the optical axis, and the amount of movement thereof is proportional to the spherical refractive power of the eye to be examined.

Reference numerals 18 and 19 are positive cylindrical lenses having the same focal length, and both lenses are rotatable about the optical axis by the same amount in the same direction or in opposite directions. As is well known, when creating a cylindrical component using two cylindrical lenses, it is necessary to take the spherical effect into account and make corrections. 2
0 is a second relay lens, 21 is an optotype plate located at the focal position of the second relay lens 20, and a fixation optotype and a general optotype are arranged in the same visual field.

In addition, in the optotype board of this example, the fixation optotype and the general optotype are arranged on one optotype board, but as described in JP-A-53-130891, It goes without saying that it may be a rotating disk on which optotypes are arranged at intervals in the direction, and that different types of optotypes can be inserted into the optical path by rotating the disk. do not have.

22 is a condensing lens, and 23 is an illumination lamp.

Figures 2 and 3 show other embodiments of the target optical system, and 18a and 19a in Figure 2 are positive cylindrical lenses with equal focal lengths, and both lenses are aligned in the same direction or in opposite directions. It is possible to rotate around the optical axis by a certain amount. In FIG. 3, 18b is a positive cylindrical lens which is movable on the optical axis. 1
9b indicates a negative cylindrical lens, and the positive cylindrical lens 1
It is designed to rotate around the optical axis together with 8b. Further, both of these cylindrical lenses and the first relay lens are movable together on the optical axis.

Figure 4 shows the first relay lens 17 in the optotype optical system.
2 is a block diagram showing a path for operating the cylindrical lenses 18 and 19. Reference numeral 24 denotes a dial provided on the side of the body (not shown), which generates a pulse signal by rotating a rotary encoder. 25 is a pulse counter, 26 is a microcomputer that controls all operations related to objective and subjective measurement, 27 is a display, 28 is a pulse motor driver, and 29 is a column by rotating the cylindrical lenses 18 and 19 around the optical axis. A pulse motor for changing the surface refractive power and the axis angle; 30 a D/A converter for converting a digital signal into an analog signal; 31
32 is a DC motor for moving the first relay lens 17 along the optical axis to change the spherical refractive power, and 32 is an A/D converter.

With the above structure, the infrared light emitted from the light source 1 passes through the condensing lenses 2 and 3, the spot diaphragm 4, and the objective lens 5, and is condensed on the cornea of the eye 8 to be examined, and reaches the fundus of the eye. On the other hand, the light from the illumination lamp 23 passes through the condensing lens 22 and projects the fixation target in the optotype plate 21 onto the fundus of the eye 8 to be examined, causing the eye 8 to fixate. The light reflected from the fundus of the eye is reflected by a mirror 10, and after passing through relay lenses 11 and 12, an image is formed on a light receiving element 16 by an imaging lens 15. The light receiving element 16 detects the incident light and supplies it to the microcomputer 26 as a digital signal. When the measurement button (not shown) is pressed after the alignment for the eye 8 to be examined is completed, the microcomputer 26
The spot diaphragm 4 and the movable lens 14 are moved until the spot diaphragm 4 is at a position conjugate with the fundus of the eye 8 to be examined.

At the same time, after the fixation target is imaged on the fundus of the eye 8 to be examined, the first relay lens 17 is moved so that it is fogged by an appropriate diopter. after that,
The measurement light source 1, the corneal reflection removal mask 13, and the measurement light receiving element 16 are moved 180° around the optical axis.
During rotation, the spot diaphragm 4 and the movable lens 14 are moved by signals from the light receiving element, and the refractive power value for each meridian can be determined from the amount of movement.

When the subjective measurement switch (not shown) is pressed after the objective measurement as described above is completed, the first relay lens 17 is moved to the position of the value obtained in the objective measurement under the control of the microcomputer 26. moves, and the cylindrical lenses 18 and 19 rotate, respectively. Therefore, the eye 8 to be examined sees the general optotype with the refractive power obtained by objective measurement corrected. In this state, if the examinee were to
If the Landolt ring corresponding to 1.0 cannot be visually recognized, perform subjective measurement using the following manual operation. Measurements are made for each of the spherical refractive power, cylindrical refractive power, and axial angle. When measuring spherical refractive power, press the spherical refractive power measurement switch and rotate the dial 24. A pulse signal is input to the microcomputer 26 by the counter 25, and the D/
The DC motor 31 operates via the A converter 30,
The first relay lens is moved on the optical axis. When measuring the cylindrical refractive power, press the cylindrical refractive power measurement switch, and when measuring the axial angle, press the axial angle measurement switch to rotate the dial 24. Then, the computer 26 activates the pulse motor 29. operates to rotate the cylindrical lenses 18 and 19. For example, the dial 24 generates a pulse by rotating 2 degrees, and the spherical and cylindrical refractive power is 0.25D.
The axis angle is set to correspond to 1°. As the dial 24 is rotated, the refractive power value is displayed on the display 27. The same applies to the embodiment shown in FIG. In the embodiment shown in FIG. 3, the first relay lens 17 and the cylindrical lenses 18b and 19b are integrally moved by the DC motor 31 to change the spherical refractive power to the cylindrical lens 18.
Set the cylindrical refractive power by moving b. Moreover, the cylindrical lenses 18b and 19b are controlled by the pulse motor 29.
rotates together to set the shaft angle.

In this embodiment, the first relay lens is moved, but the same effect can be obtained by moving other optical elements in the optotype optical system, such as the second relay lens, optotype, etc. It will be done.

Furthermore, although the present embodiment has been described using an objective type automatic refractive power measuring device as an example, it is obvious that the present invention can also be applied to a semi-manual type device. Furthermore, it goes without saying that the correction optical system disposed within the target optical system is not limited to that described in this embodiment.

As is clear from the above explanation, by arranging the optical system for measuring subjective refractive power in the fixation target projection system, it is possible to quickly and accurately measure the subjective refractive power with one device. Subjective measurement becomes possible. Further, since the members in the visual target projection system for fixation can also be used for subjective optometry, the number of common parts can be increased, and the apparatus can be made compact.

[Brief explanation of drawings]

FIG. 1 is an optical system layout diagram of an eye refractometer according to the present invention, FIGS. 2 and 3 are optical system layout diagrams showing other embodiments of the target optical system, and FIG. 4 is a block diagram. be. 1...Light source for measurement, 4...Spot aperture, 5,
6... Objective lens, 8... Eye to be examined, 13... Corneal reflection removal mask, 14... Moving lens, 16...
Light receiving element, 17...first relay lens, 18,1
9...Cylindrical lens, 21...Optotype board.

Claims (1)

[Claims] 1. In an eye refractive power measuring device capable of projecting a measurement optotype onto the fundus of the eye to be examined, detecting the image of the optotype on the fundus of the eye to be examined, and obtaining refractive power information of the eye to be examined,
In the fixation target projection system that projects the fixation target, the means for presenting the target for subjective ophthalmoscopy, the axis angle (AXIS), the cylindrical refractive power (CYL), and the spherical refractive power (SPH) are included. This eye refractive power measuring device is equipped with a variable corrective optical system and enables subjective refractive power measurement of the eye being examined.