JPH0994229A - Apparatus for photographing endothelial cell of cornea - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for photographing corneal endothelial cells without narrowing the tolerance of alignment and keeping a high alignment precision. SOLUTION: This apparatus comprises a lighting optical system 25 for lighting a cornea C, an observing and photographing optical system 26 for observing and photographing by receiving the reflected image from the cornea C, a means for detecting the focusing state 65 which detects the focusing state of the endothelial cells of the cornea, a lighting optical system for lighting the eye anterior region 31, an observing optical means 21 for observing the anterior part of the eye of the subject E, an alignment index projecting means 22 for projecting an alignment index light to the subject eye E, alignment detecting means 36 and 42 for aligning the apparatus to the subject eye E. The alignment detecting means are capable of switching between a state being wide in range for detection and low in precision for detection and a state being narrow in range for detection and high in precision for detection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corneal endothelial cell observation and photographing device for observing and photographing corneal endothelial cells.

[0002]

2. Description of the Related Art Conventionally, as a corneal endothelial cell observation and photographing device for observing and photographing a corneal endothelial cell image of an eye to be inspected, an illumination optical system for obliquely irradiating illumination light to the cornea of the eye to be inspected, and corneal endothelial cells It is known to include an observation / photographing optical system for observing / photographing the reflected light from the cornea from an oblique direction including the above, and an alignment detection optical system for aligning the apparatus body with respect to the eye to be examined.

[0003]

However, this conventional corneal endothelial cell observation and imaging device has only one alignment detection optical system, and a low-magnification light-receiving lens is used to widen the size of the detection range. If this is used, the position detection accuracy will decrease, and if a high-magnification light receiving lens is used to increase the position detection accuracy, the size of the detection range will be narrowed. It is difficult to improve the accuracy with the conventional corneal endothelial cell observation and imaging device, and the examiner usually observes the anterior segment image so that the alignment index by the alignment detection optical system is displayed on the screen. However, it is necessary to move the device, but in order to reduce the burden on the examiner, the size of the detection range (alignment allowance range) should be increased in order to increase the light receiving lens. The position detection accuracy (alignment accuracy) decreases when a low-magnification lens is used, and the corneal endothelial cell image tends to be out of focus. When a high-magnification light receiving lens is used, the size of the detection range (alignment accuracy) increases. The allowable range) becomes narrower and the burden on the examiner regarding the alignment operation increases. Some corneal endothelial cell observation and imaging devices have a configuration that automatically moves the device body based on an alignment detection signal.
The examiner must manually move the device body until the alignment of the device body with respect to the eye to be examined falls within a predetermined detection range, and the above problems cannot be basically solved.

As described above, in the conventional corneal endothelial cell observing and photographing apparatus, if the size of the alignment detection range (allowable alignment range) is widened, the position detection accuracy (alignment accuracy) decreases, and the position detection accuracy (alignment accuracy). There is a problem that the size of the alignment detection range (alignment allowable range) becomes narrower in an attempt to increase the height of the cornea, and the present invention aims to provide a corneal endothelial cell observation / imaging device capable of solving this problem. And

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 provides an illumination optical system for illuminating the cornea of an eye to be examined obliquely, and the corneal endothelial cells. Including an observation and imaging optical system for receiving and observing the reflected image from the cornea, and imaging, an in-focus state detecting unit for detecting an in-focus state of the corneal endothelial cells, and illuminating the anterior segment of the eye to be examined. Anterior segment illumination optical system, anterior segment observation optical system for observing the anterior segment of the subject's eye, alignment index light projecting means for projecting alignment index light on the subject's eye, and reflection index from the subject's eye Alignment detection means for detecting the light flux and aligning the apparatus main body with respect to the eye to be inspected. The alignment detection means has a wide detection range and a low position detection accuracy and a small detection range. Narrow position detection Characterized in that it is switchable between a high state.

According to a second aspect of the present invention, in the first aspect of the invention, a state in which the detection range of the alignment detecting means is wide and the position detection accuracy is low is achieved by the anterior segment observation optical system. It is characterized by being done.

According to a third aspect of the present invention, in the invention according to the first aspect, the apparatus main body is arranged so that the apparatus main body is aligned with the eye to be inspected based on the detection information of the alignment detecting means. The driving means for driving is provided.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 is a side view showing the configuration of the corneal endothelial cell observation and photographing device of the present invention, in which 1 is a base with a built-in power source. A base 2 is provided above the base 1 so as to be movable back and forth and left and right by operating a control lever 3.
The control lever 3 is provided with a photographing switch 4,
The photographing switch 4 is used in the manual photographing mode. A motor 5 and a support 6 are provided on the top of the gantry 2. The motor 5 and the support 6 are connected by a pinion rack (not shown), and the support 6 is moved up and down by the motor 5. A table 7 is provided at the upper end of the column 6.

A column 8 and a motor 9 are provided on the table 7. A table 10 is slidably provided on the upper ends of the columns 8. A rack 11 is provided at the rear end of the table 10 as shown in FIG. The output shaft of the motor 9 is provided with a pinion 12, and the pinion 12 is the rack 1
1 is engaged. Further, a motor 13 and a support 14 are provided on the upper portion of the table 10. Motor 1
A pinion 15 is provided on the output shaft of 3. Prop 1
An apparatus body case 16 is slidably provided on the upper portion of the device 4. A rack 17 is provided on the side of the apparatus body case 16. The rack 17 is meshed with the pinion 15. Reference numeral 100 is a control unit that processes signals and controls the motors 9 and 13 and the like. The main body of the apparatus is automatically driven based on the alignment information in the up, down, left, right, front, and back directions with respect to the eye to be inspected, the details of which will be described later.

Inside the apparatus main body case 16 is shown in FIG.
The optical systems shown in (B) and (C) are housed. This optical system includes an anterior segment observation optical system 21 for observing the anterior segment of the eye E, an alignment index light projection optical system 22 for projecting index light onto the cornea C of the eye E, and a fixation target light on the cornea C. Fixation target light projection optical system 23 for projecting an image, an alignment pattern projection optical system 24 used in the alignment operation between the apparatus body and the eye to be inspected, an illumination optical system 25 for obliquely irradiating the cornea C with illumination light, and a cornea An observation / photographing optical system 26 for observing / photographing a C corneal endothelial cell image is provided. Anterior segment observation optical system 21
Is a pair of anterior ocular segment observation light sources 31, which are located on the left and right of the eye E to directly illuminate the anterior ocular segment, a half mirror 32,
The objective lens 33, the half mirror 34, the light shield plate 35 that is retracted from the optical path when observing the anterior segment of the eye, and is inserted into the optical path when observing and photographing the cornea C, and the CCD camera 36 are provided.
Is the optical axis of the optical path. The anterior ocular segment image of the subject's eye E illuminated by the anterior ocular segment illumination light source 31 passes through the half mirror 32, and then is guided to the CCD camera 36 via the objective lens 33 and the half mirror 34.

As shown in FIG. 1B, the alignment index light projection optical system 22 focuses on the alignment light source 37 for emitting infrared light, the pinhole plate 38, the half mirror 39, and the pinhole plate 38. The projection lens 40, the diaphragm 41, and the half mirror 32 arranged on the optical path in this manner
Having. The alignment index light K emitted from the alignment light source 37 and passing through the pinhole plate 38 is reflected by the half mirror 39, converted into a parallel light flux by the projection lens 40, passes through the diaphragm 41, and is reflected by the half mirror 32. Then, the alignment index light K is guided to the cornea C, and as shown in FIG. 1C, a bright spot image R is formed at an intermediate position between the apex P of the cornea C and the curvature center O2 of the cornea C. Thus, the light is reflected by the corneal surface T. The reflected index light flux from the cornea C is guided to the half mirror 34 via the half mirror 32 and the objective lens 33. A part of the reflection index light flux guided to the half mirror 34 is part of the half mirror 34.
It is reflected by and is guided to the alignment detection sensor 42 capable of detecting the position of PSD or the like. The remaining reflection index light flux passes through the half mirror 34 and is guided to the CCD camera 36.
The fixation target light projection optical system 23 includes a fixation target light source 43 that emits visible light, a pinhole plate 44, a half mirror 39, a projection lens 40, a diaphragm 41, and a half mirror 32. The fixation target light emitted from the fixation target light source 43 passes through the pinhole plate 44 and the half mirror 39 to be a parallel light flux by the projection lens 40, passes through the diaphragm 41, and is reflected by the half mirror 32. . The subject is this half mirror 32
The line of sight is fixed by gazing at the fixation target light reflected by the eye as a fixation target.

The alignment pattern projection optical system 24 is
A rectangular frame-shaped pattern is formed on an alignment pattern plate 46 including a projection lens 47, an alignment pattern projection light source 45, and an alignment pattern plate 46 provided so as to face the half mirror 34, and a pattern transmitted through the alignment pattern plate 46. The formed light flux is reflected on the back surface of the half mirror 34 and is focused on the CCD camera 36. The CCD camera 36 outputs an image signal to the monitor device. On the screen 48 of the monitor device, as shown in FIGS. 2 (A) to 2 (C), the eye E to be inspected
The anterior segment image E ′, the bright spot image R ′ corresponding to the bright spot R, the rectangular frame pattern image 42 ′, and the pair of bright spot images 31 ′ based on the pair of anterior segment illumination light sources 31 are displayed. The symbol Pu indicates a pupil.

The interval between the pair of bright spot images 31 'and the size thereof vary depending on the distance in the Z direction between the apparatus body and the eye E to be examined, and as shown in FIG. 2 (A), the apparatus body and the eye E to be examined. When the distance in the Z direction from E is approximately the proper working distance, the light amount distribution is sharp and the predetermined distance L determined by the optical design is obtained, and the distance in the Z direction between the apparatus main body and the eye E is proper. When the distance is larger than the working distance, the light quantity distribution is blurred and a distance L0 smaller than the predetermined distance L is obtained. When the distance in the Z direction between the apparatus body and the eye E is smaller than the proper working distance, the light quantity distribution pp is An interval L0 ′ that is blurry and larger than the predetermined interval L is obtained. Therefore, by observing the interval between the pair of bright spot images 31 ′ and 31 ′ and the brightness thereof, the device main body is at an appropriate working distance with respect to the eye E, whether it is too close to the eye E, or the eye E. You can determine if it is too far from.

Therefore, the CCD camera 36 and the pair of anterior ocular segment illumination light sources 31 function as alignment detecting means, and the detection range of the CCD camera 36 is the entire area of the image receiving surface (the entire display surface of the screen 48). However, the position detection accuracy of the CCD camera 36 is low because the light source 31 originally used to illuminate the anterior segment is used for alignment detection. On the other hand, the alignment detection sensor 42 is provided only for detecting alignment, and its detection range is narrower than the detection range of the CCD camera 36 and its position detection accuracy is high, and FIG. 2D shows the CCD camera 36.
Alignment detection range and alignment detection sensor 42
The reference numeral 42a indicates the detection range of the alignment detection sensor 42, and the reference numeral 48a indicates the detection range of the CCD camera 36.

The control unit 100 calculates the amount of deviation from the proper working distance based on the detection signal of the CCD camera 36, and automatically controls the apparatus main body in the direction in which the amount of deviation becomes smaller. CC is below a predetermined value
The detection range based on the D camera 36 is switched to the detection range based on the alignment detection sensor 42.

The position of the apparatus main body in the vertical and horizontal directions with respect to the eye E is detected by the position of the bright spot image R '.
As shown in (E), the bright spot image R ′ has a rectangular frame-shaped pattern 4
When it is outside the 2'position (the amount of deviation from the center is Δ
x, Δy), the control unit 100 calculates the amount of shift in the vertical and horizontal directions based on the detection signal of the CCD camera 36, and detects the alignment when the bright spot image R ′ is inside the position of the rectangular frame pattern 42 ′. The amount of shift in the vertical and horizontal directions is calculated based on the output of the sensor 42, and the optical axis of the device body is automatically driven so as to match the optical axis of the eye to be inspected.

In this way, the alignment adjustment of the device main body with respect to the eye E to be inspected is performed in the vertical, horizontal, and front-back directions.

The illumination optical system 25 includes an observation illumination light source 49 including a halogen lamp, a condenser lens 50, an infrared filter 51, and a photographing illumination light source 52 including a xenon lamp.
It has a condenser lens 53, a dichroic mirror 54, a slit plate 55, a light projecting lens 56, and an aperture stop 57, and O3 is its optical axis. Note that the observation illumination light source 49 uses an infrared LE.
When D is used, the infrared filter 51 is unnecessary. The observation illumination light source 49 emits light during observation, the photographing illumination light source 52 emits light during photographing, and the infrared light emitted from the observation illumination light source 49 is collected by the condenser lens 50 and passed through the infrared filter 51. Transparent, dichroic mirror 5
The visible light emitted from the photographing illumination light source 52 after being reflected by 4 and guided to the slit plate 55 is condensed by the condenser lens 53 and transmitted through the dichroic mirror 54 to be guided to the slit plate 55. The light flux that has passed through the slit plate 55 passes through the light projecting lens 56 and the aperture stop 57 to form the cornea C.
The cornea C is cross-illuminated. FIG. 3 shows a reflection state of slit light from the surface of the cornea and the corneal endothelium, and a part of the slit light flux is first reflected on the corneal surface T which is a boundary surface between the air and the cornea C. The corneal surface T
The amount of reflected light flux L from is the largest. The light quantity of the scattered reflected light flux M from the corneal endothelial cell N is relatively small. The light amount of the reflected light beam L 'from the corneal stroma M' is the smallest.

The observation / photographing optical system 26 includes an objective lens 58,
Half mirror 59, mask 60, total reflection mirror 61, relay lens 62, optical path when observing the anterior segment (on optical axis O4)
The light-shielding plate 63 that is inserted into the inside of the cornea C and is retracted from the optical path when observing / photographing the cornea C, is arranged at a position that does not interfere with the observation light flux of the anterior segment, and is inclined at the object side (eye E side). Total reflection mirror 64, CC which is inclined at the same angle as θ, CC
It has a D camera 36, and O4 is its optical axis. The reflected light flux from the cornea C is condensed by the objective lens 58 and guided to the half mirror 59. A part of the light flux reflected from the cornea C is reflected by the half mirror 59 and guided to the focus position detection sensor 65, and the rest of the light flux reflected from the cornea C passes through the half mirror 59. The reflected light flux that has passed through the half mirror 59 is once imaged at the position of the mask 60, and the mask 60 shields the extra reflected light flux other than forming the corneal endothelial cell image. The reflected light flux passing through the mask 60 is reflected by the total reflection mirror 61, is focused by the relay lens 62 and is reflected by the total reflection mirror 64, and then C
An image of corneal endothelial cells is formed on the CD camera 36 at high magnification. The position of the mask 60 is at the focal position of the corneal endothelial cell image with visible photographing light. Further, the corneal endothelial cell image on the CCD camera 36 is also at the focus position with visible photographing light.

The in-focus position detecting sensor 65 is, here,
4 (a), the horizontal axis indicates the address of each element forming the line sensor, and the vertical axis indicates the amount of light on each element, with respect to the cross-sectional direction of the cornea C. Thus, the focus position detection sensor 65 is arranged as shown in FIG. 4B, and the intensity distribution of the reflected light flux from the cornea C is as shown in FIG. In FIG. 4 (a), the symbol U is a peak due to the reflected light flux reflected on the surface T of the cornea C, the symbol V is the peak of the endothelial cell portion of the cornea C, and the peak U corresponds to the optical image 67 and the peak. V
Corresponds to the optical image 68. The output of the element at each address of the focus position detection sensor 65 is input to the focus determination circuit 66, and the focus determination circuit 66 detects all the peaks U and V as shown in FIG. The address of the peak V is determined by storing the signal and performing arithmetic processing. Then, the focus determination circuit 66 determines whether or not the address L of the peak V coincides with the center address Q of the focus position detection sensor 65, and thus the focus state of the corneal endothelium (accurate in the Z direction). Alignment) can be detected.

That is, the control unit 100 causes the apparatus main body H to move away from and approach the anterior ocular segment of the subject's eye E (moves the optical system of the apparatus in the Z direction) in a minute range, whereby the address L of the peak V is determined. Moving. The device body H is the address L of the peak V
Since the corneal endothelium is designed to be focused when the center address Q coincides with the center address Q, the focus determination circuit 66 outputs a focus signal when the address L of the peak V coincides with the center address Q. As a result, the illumination light source 31 emits light, the eye E to be inspected is illuminated with visible light, and photographing is automatically performed.

In the present invention, the alignment detecting means can automatically switch between a state in which the size of the detection range is wide and the position detection accuracy is low, and a state in which the size of the detection range is narrow and the position detection accuracy is high. , It was configured to automatically drive the device body with respect to the eye to be inspected, but when the detection range is wide and the position detection accuracy is low, the device body is manually moved relative to the eye. Automatically, it automatically switches from the state where the detection range is wide and the position detection accuracy is low to the state where the detection range is narrow and the position detection accuracy is high, and the position is narrow due to the narrow detection range. The apparatus main body may be automatically driven to perform alignment when the detection accuracy is high.

[0024]

Since the present invention is configured as described above, a wide range of alignment detection can be performed by combining the anterior segment illumination and the anterior segment observation system without using a separate optical system for detecting alignment. (Position detection) is possible, and operability is improved. Then, when the alignment accuracy falls within a predetermined range, by using a more accurate alignment sensor (focus position detection sensor), it is possible to perform more accurate alignment. Further, when the detection information of the highly accurate alignment sensor (focus position detection sensor) is used for the corneal thickness measurement, it can be applied to the alignment error correction of the corneal thickness measurement data.

[Brief description of drawings]

FIG. 1 shows an optical system of a corneal endothelial cell imaging apparatus of the present invention, (A) is an explanatory view of a main optical system, (B) is an explanatory view of an alignment index light projection optical system and a fixation target projection optical system, (C)
FIG. 4 is an explanatory diagram showing a cornea reflection state of index light.

FIG. 2 shows an anterior segment image displayed on a monitor screen,
(A) shows a state in which the device body is at an appropriate working distance with respect to the eye, (B) shows a state in which the device body is too far from the eye, and (C) shows the device body with respect to the eye. Shows a state that is too close, and (D) shows the relationship between the detection range by the CCD camera and the detection range by the alignment sensor.
(E) shows a state in which the apparatus main body is displaced vertically and horizontally with respect to the eye to be inspected.

FIG. 3 is an explanatory diagram showing a reflection state of a slit light beam on a cornea.

FIG. 4 shows the relationship between the corneal endothelial cell image and the amount of light received by the focus position detection sensor, (a) shows the light amount distribution on the focus position detection sensor, and (b) shows the relationship with the corneal endothelial cell image. It is a figure which shows the relationship with a focus position detection sensor.

FIG. 5 is a plan view showing a main part of a corneal endothelial cell observation and imaging device according to the present invention.

FIG. 6 is a side view showing the overall configuration of a corneal endothelial cell observation and imaging device according to the present invention.

[Explanation of symbols]

 C ... Corneal E ... Eye to be examined N ... Endothelium 21 ... Anterior segment observation optical system 22 ... Alignment index light projection means 25 ... Illumination optical system 26 ... Observation / photographing optical system 31 ... Anterior segment illumination optical system 36 ... CCD camera 42 ... Alignment sensor 65 ... Focusing state detection means 100 ... Control unit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiko Yukake 75-1 Hasunuma-cho, Itabashi-ku, Tokyo Topcon Co., Ltd. (72) Inventor Masakazu Hayashi 75-1 Hasunuma-cho, Itabashi-ku, Tokyo Top Co., Ltd. In the con

Claims (3)

[Claims] 1. An illumination optical system for illuminating the cornea of an eye to be examined obliquely, and an observation and photographing optical system for receiving and observing and photographing a reflection image from the cornea including the corneal endothelial cells. An in-focus state detecting means for detecting the in-focus state of the corneal endothelial cells; an anterior ocular segment illumination optical system for illuminating the anterior segment of the subject's eye; and an anterior segment for observing the anterior segment of the subject's eye. An observation optical system, an alignment index light projecting means for projecting alignment index light on the eye to be examined, and an alignment detecting means for receiving and detecting a reflection index light beam from the eye to align the apparatus main body with respect to the eye to be examined. The alignment detection means is switchable between a state in which the size of the detection range is wide and the position detection accuracy is low, and a state in which the size of the detection range is narrow and the position detection accuracy is high. Corneal endothelial cells Observation and photography device. 2. The corneal endothelial cell according to claim 1, wherein a state in which the detection range of the alignment detecting means is wide and the position detection accuracy is low is achieved by the anterior segment observation optical system. Observation and photography device. 3. A drive unit for driving the apparatus body so that the apparatus body is aligned with the eye to be inspected based on the detection information of the alignment detection unit. The apparatus for observing and observing corneal endothelial cells according to item 1.