JPH07116121A - Ophthalmic apparatus - Google Patents

Abstract

PURPOSE:To enable highly accurate measurement by eliminating the influence of eyelashes, etc., in an ophthalmic apparatus of photorefraction system. CONSTITUTION:In an ophthalmic apparatus of photorefraction system that projects a measuring light to the fundus of a subject's eye, picks up the image of the beam of light in the pupil of the subject's eye by a photo-reception device and measures the refractivity of the subject's eye from the results. The ophthalmic apparatus has a storage device 17 storing the image from the photo- reception device 9 and a processing unit 16 that synthesizes at least two picked-up images in the storage device and operates the ophthalmic information based on the obtained image. Undesirable factors such as the influence of eyelashes are compensated by synthesizing at least two picked-up images. The ophthalmic measurement information is operated based on the synthesized image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus for performing ophthalmologic measurement of eye refractive power and the like, and more particularly to an ophthalmologic apparatus capable of eliminating the influence of eyelashes.

[0002]

2. Description of the Related Art As an ophthalmologic apparatus, a measurement light is projected on the fundus of the eye to be examined, and the state of the light flux in the pupil of the eye to be examined is imaged by a photoreceiver, and the eye refraction power of the eye to be examined is measured from the result. There is an ophthalmic device.

The applicant of the present invention has previously mentioned in Japanese Patent Application No. 1-24941 (Japanese Patent Application Laid-Open No. 2-191428) a photorefraction for measuring the eye refractive power from the inclination of the distribution of the amount of light on the light receiving surface of the light receiver. Proposed and realized a new type of ophthalmic device.

The ophthalmologic apparatus proposed in Japanese Patent Application No. 1-24491 will be briefly described with reference to FIG.

In FIG. 18, reference numeral 1 designates a light source image as an eye 3 to be examined.
Is a projection system for projecting onto the fundus 7 of the eye, 2 is a light receiving system for receiving the light flux 10 reflected by the fundus 7, and the projection system 1 and the light receiving system 2 are arranged facing the eye 3 to be examined. It

The projection system 1 comprises a light source 4 and a half mirror 5 for reflecting a light beam 11 from the light source 4 toward an eye 3 to be examined. The projection system 1 passes the light beam 11 from the light source 4 through a pupil 6. The image is projected so as to form an image of the light source 4 on the fundus 7, and when the eye refractive power of the eye 3 is the reference diopter value (reference refractive power), the image of the light source 4 is focused on the fundus 7. Thus, the distance between the light source 4 and the subject's eye 3 is set.

The light receiving system 2 is composed of an objective lens 8 and a light receiver 9, and a light beam 10 from the fundus 7 passes through the half mirror 5 and is guided onto the light receiver 9.

The light receiver 9 is an area CCD or an image pickup tube, and the light receiving surface 9a of the light receiver 9 is arranged at a conjugate position with the pupil 6 of the eye 3 to be examined with respect to the objective lens 8.

In the optical path of the light receiving system 2, the optical axis O of the objective lens 8 is located at a position conjugate with the light source 4 with respect to the half mirror 5.
The edge-shaped light-shielding member 12 whose tip is aligned with is arranged.

An arithmetic unit 13 is connected to the light receiver 9, and the arithmetic unit 13 calculates a diopter value from the light receiving state of the light receiver 9 and the light amount distribution, and outputs the result to the display unit 14. Has become.

In FIG. 18, the eye 3 to be examined has a reference eye refractive power (reference diopter value). In this case, the image of the light source 4 is formed on the fundus 7, and the reflected light flux 10 from the fundus 7 is shielded. A light source image is formed on the edge of the member 12.

However, when the eye 3 to be inspected deviates from the reference diopter value, the state of being shielded by the light shielding member 12 changes, and the light amount distribution of the pupil image on the light receiving surface 9a is orthogonal to the edge of the light shielding member 12. The distribution of the amount of light is shown.

Thus, the eye refractive power of the eye 3 to be inspected can be measured by detecting the inclination of the light amount distribution of the light receiving surface 9a.

Further, the pupil diameter of the eye 3 to be inspected is u, the deviation ΔD of the diopter value from the reference diopter value of the eye 3 to be inspected,
If the slope of the light quantity distribution is I,

[0015]

## EQU1 ## ΔD = CI / u (C is a constant).

Further, FIG. 19 (A) shows the light quantity distribution.
As shown in (B), there is a sudden drop in light amount p, q at the boundary between the pupil 21 and the iris 22. Therefore, the pupil diameter u necessary for obtaining the deviation ΔD of the diopter value can be obtained by detecting the sudden light amount reduction positions r and s of the light amount distribution.

[0017]

In the above-described ophthalmologic apparatus, the light receiving surface 9 corresponding to the light blocking state of the light flux 10 from the fundus of the eye.
The light intensity distribution on a is measured. Therefore, if the state where the light beam 10 is shielded by a part other than the light shielding member 12 does not occur, the information itself of the eye 3 to be obtained obtained by the light amount distribution becomes inaccurate. In particular, the light flux 10 is often shielded by the eyelashes of the eye to be inspected, and due to the effect of the eyelashes, it is impossible to accurately detect the position of the pupil or the pupil diameter u, resulting in erroneous recognition and erroneous detection.

In view of the above situation, the present invention is capable of accurately detecting the pupil position and the pupil diameter even when the light beam 10 is blocked by the eyelashes.

[0019]

According to the present invention, a measuring light is projected onto a fundus of an eye to be inspected, a state of a light flux in a pupil of the eye to be inspected is imaged by a light receiver, and the eye refractive power of the eye to be inspected is measured from the result. In a photorefraction type ophthalmologic apparatus, a memory for storing an image pickup screen from a light receiver and two or more image pickup screens of the memory are combined, and ophthalmic measurement information is calculated based on the obtained image. It is characterized by comprising an arithmetic processing unit.

[0020]

By combining two or more image pickup screens, unfavorable factors such as the influence of eyelashes are offset, and ophthalmic measurement information is calculated from the combined image, so that highly accurate measurement can be performed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 3, the same components as those shown in FIG. 18 are designated by the same reference numerals.

As shown in FIG. 2, the light shielding member 12 is a circular plate having a square light transmitting hole 15 formed in the center thereof, and when each side of the light transmitting hole 15 shields the light beam 10. Edge 15
a, 15b, 15c, 15d. The light source 4 is shown in FIG.
As can be seen in FIG. 4, four sets of linear luminous bodies 4a, 4b, 4c, 4d arranged on a line orthogonal to the optical axis of the projection system 1 are arranged.
And the linear luminous bodies 4a, 4b, 4c and 4d are orthogonal to the edges 15a, 15b, 15c and 15d, respectively.

The arithmetic unit 13 includes an arithmetic processor 16, a memory 17, and a light source driver 18, and a light reception signal from the light receiver 9 is taken in and stored in the memory 17, and the arithmetic processing is performed. The light source 4 via the light source driver 18
Each of the linear luminous bodies 4a, 4b, 4c, 4d is sequentially turned on.

The operation will be described below.

One of the linear luminous bodies 4a, 4b, 4c and 4d, for example, the linear luminous body 4 is driven by the light source driver 18.
FIG. 4 is an image in which a is turned on and light is received by the light receiver 9 at that time.
(A) is stored in the storage unit 17. Furthermore, in the arithmetic processor 16, the image stored in the memory 17 is shown in FIG.
Regarding (A), a horizontal light amount distribution diagram 4 (B) and a vertical light amount distribution diagram 4 (C) are obtained.

Next, the linear light-emitting body 4b is turned on, and the image shown in FIG.
7 and the image FIG. 5 (A) stored in the storage unit 17 in the arithmetic processing unit 16 in the same manner, the horizontal light amount distribution diagram 5 (B) and the vertical light amount distribution diagram 5 (C). Similarly.

Subsequently, the linear luminous body 4c and the linear luminous body 4d.
6B in the horizontal direction, FIG. 6C in the vertical direction, and FIG. 7C in the horizontal direction, and FIG. 7C in the vertical direction when the is turned on. Similarly.

4 (B), 5 (B) and 6
If the average value of the light amount distributions of (B) and FIG. 7 (B) is obtained, a rectangular light amount distribution obtained by averaging the inclinations of FIG. 5 (B) and FIG. 7 (B) is obtained. And FIG. 4 (C) and FIG.
If the average values of the light amount distributions of (C), FIG. 6 (C), and FIG. 7 (C) are obtained, the inclinations of FIG. 4 (C) and FIG. 6 (C) are similarly canceled and averaged. A rectangular light amount distribution is obtained. Therefore, if the boundary position of the pupil is obtained from the averaged rectangular light amount distribution, the rising position and the falling position of the light amount distribution become clear, and the boundary position of the pupil, that is, the pupil diameter can be easily obtained.

Next, the case where the image projected on the light receiver 9 is affected by eyelashes will be described with reference to FIGS.

Each linear luminous body 4 is driven by the light source driver 18.
a, 4b, 4c, and 4d are sequentially turned on, and the light amount distribution in each horizontal direction and each vertical direction at that time is obtained. In addition, FIG.
9 (A), 10 (A), and 11 (A) show the case where each of the linear luminous bodies 4a, 4b, 4c, and 4d is sequentially turned on,
The images each include a pupil portion of the eye to be inspected.

FIG. 8A, FIG. 9A, FIG. 10A,
As shown in FIG. 11A, the influence 20 of the eyelashes is shown by the vertical line. Horizontal light amount distributions obtained from these images are shown in FIGS. 8B, 9B, 10B, and 11.
It shows with (B). Also in this light amount distribution, there is a light amount drop 19 at a position corresponding to the eyelash portion.

As can be seen from the structure shown in FIG. 1, each of the linear luminous bodies 4a, 4b, 4c, 4d and the edge 15 are formed.
Since a, 15b, 15c, and 15d are slightly deviated from the optical axis of the eye to be inspected, the above-mentioned FIG. 8 (A), FIG. 9 (A), and FIG.
(A), image of FIG. 11 (A), FIG. 8 (B), FIG.
The horizontal position (X coordinate position) of the drop of the light amount corresponding to the eyelash portion is shifted in the light amount distributions of (B), FIG. 10 (B), and FIG. 11 (B).

Therefore, the image memory stored in the storage unit 17, FIG. 8 (A), FIG. 9 (A), FIG. 10 (A), and FIG.
(A) If the light intensity value at each point on the image memory is sampled and the maximum light intensity value of the sampled light intensity values is combined to recreate the image and the light intensity distribution,
As shown in FIGS. 2 (A) and 12 (B), an image and a light amount distribution without the influence of eyelashes can be obtained. An accurate boundary position of the pupil, that is, the pupil diameter can be easily obtained from the light amount distribution in which the influence of the eyelashes is removed.

Further, as another image processing method for reducing the influence of eyelashes, there is one shown in FIGS.

Each of the linear luminous bodies 4a, 4b, 4c, 4d
Image memories including the pupil portion of the eye to be inspected, which are obtained by sequentially illuminating, respectively, FIG. 13 (A), FIG. 14 (A),
15A and FIG. 16A, image memories having opposite inclinations. FIG. 14A and FIG. 16A are rotated by 90 °, respectively, and obtained image memory FIG. 14C and FIG. 16 (C)
If the image memory 4 shown in FIG. 13 (A) and FIG. 15 (A) is sampled with the light amount value at each point on the image memory and the maximum light amount value among the sampled light amount values is combined. As shown in FIG. 17A, if an image is recreated, an image memory with almost no influence of eyelashes can be obtained as shown in FIG. 17B. When the light amount distribution is created by the image memory shown in FIG.
The light amount distribution of (B) is obtained, and the accurate boundary position of the pupil, that is, the pupil diameter, can be easily obtained as described above.

As a method of capturing the image graduation, one frame memory may be captured every time each of the linear luminous bodies 4a, 4b, 4c, 4d is turned on, or a memory may be stored as an image on horizontal and vertical scanning lines. You may.

In the above embodiment, the image memory is recombined by the image memory of 4, but the image memory may be recomposed based on the image memory of 2 or 3 or the image memory of 4 or more.

[0039]

As described above, according to the present invention, when the ophthalmologic measurement of the eye to be inspected is carried out by the imaged image memory, it is possible to remove the influence of eyelashes and perform accurate measurement.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a view on arrow AA of FIG.

3 is a BB arrow view of FIG. 2. FIG.

4A is a diagram showing an imaged screen, FIG. 4B is a horizontal light amount distribution diagram of the imaged screen, and FIG. 4C is a vertical light amount distribution diagram of the imaged screen.

5A is a diagram showing an imaged screen, FIG. 5B is a horizontal light amount distribution diagram of the imaged screen, and FIG. 5C is a vertical light amount distribution diagram of the imaged screen.

6A is a diagram showing an imaged screen, FIG. 6B is a horizontal light amount distribution diagram of the imaged screen, and FIG. 6C is a vertical light amount distribution diagram of the imaged screen.

7A is a diagram showing an imaged screen, FIG. 7B is a horizontal light amount distribution diagram of the imaged screen, and FIG. 7C is a vertical light amount distribution diagram of the imaged screen.

8A is a diagram showing an imaged screen, and FIG. 8B is a horizontal light amount distribution diagram of the imaged screen.

9A is a diagram showing an imaged screen, and FIG. 9B is a horizontal light amount distribution diagram of the imaged screen.

10A is a diagram showing an imaged screen, and FIG. 10B is a horizontal light amount distribution diagram of the imaged screen.

11A is a diagram showing an imaged screen, and FIG. 11B is a horizontal light quantity distribution diagram of the imaged screen.

FIG. 12 is a horizontal light amount distribution chart obtained from (A) an image-capturing screen and (B) a composite screen.

13A is a diagram showing an imaged screen, and FIG. 13B is a horizontal light amount distribution diagram of the imaged screen.

14A is a diagram showing an imaged screen, FIG. 14B is a horizontal light amount distribution diagram of the imaged screen, and FIG. 14C is a diagram showing a screen obtained by rotating the imaged screen by 90 °.

15A is a diagram showing an imaged screen, and FIG. 15B is a horizontal light amount distribution diagram of the imaged screen.

16A is a diagram showing an imaged screen, FIG. 16B is a horizontal light amount distribution diagram of the imaged screen, and FIG. 16C is a diagram showing a screen obtained by rotating the imaged screen by 90 °.

FIG. 17 (A) is a diagram showing a screen synthesized from the imaging screen;
FIG. 7B is a horizontal light amount distribution diagram obtained from the composite screen.

FIG. 18 is a basic configuration diagram showing a conventional ophthalmologic apparatus.

19 (A) and (B) are diagrams showing the relationship between the image pickup screen and the light amount distribution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection system 2 Light receiving system 3 Eye to be inspected 4 Light source 5 Half mirror 6 Pupil 7 Fundus 8 Objective lens 9 Light receiver 10 Luminous flux 13 Arithmetic device 16 Arithmetic processor 17 Memory device 18 Light source driver

Claims (3)

[Claims] 1. A photorefraction type ophthalmologic apparatus which projects measurement light onto the fundus of the eye to be inspected, images the state of the light flux at the pupil of the eye to be inspected by a light receiver, and measures the eye refractive power of the eye to be inspected from the result. In the above, a storage device for storing an image pickup screen from the light receiver and an arithmetic processing unit capable of synthesizing two or more image pickup screens of the storage device and calculating ophthalmic measurement information based on the obtained image are provided. Ophthalmic device characterized by. 2. The ophthalmologic apparatus according to claim 1, wherein at least one of the two or more image pickup screens is rotated and combined. 3. A light source for projecting measurement light onto a fundus of an eye to be inspected has a plurality of light emitters, the light emitters can be individually turned on, and the light emitters are arranged to be displaced from an optical axis of the eye to be inspected. The ophthalmic device according to claim 1.