JPH0430855B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention has the function of an autorefractometer that measures diopter, astigmatism, etc. of the eye, and furthermore, the autorefractometer and the autorefractometer that measures corneal curvature. This invention relates to an eye measuring device that has both the functions of an autokeratometer.

[Conventional technology]

Conventionally, autorefractometers equipped with one-dimensional CCDs in three radial directions, and furthermore, so-called autoreflux keratometers capable of measuring both ocular refraction values and corneal curvature have been known.

However, since a one-dimensional CCD has a finite width, the light beam tends to deviate. It is known that a cylindrical lens is used to compensate for this, but in this case, although information on the position of the light beam in the radial direction is detected,
The light beam position information in the direction perpendicular to the radial line is buried and cannot be detected.

[Purpose of the invention]

An object of the present invention is to provide an improved eye measurement device that can also detect light flux position information in the direction perpendicular to the radial line.

[Summary of the invention]

The gist of a first invention for achieving the above-mentioned object is to include a projection optical system that projects an index onto the fundus of an eye to be examined, and a detection optical system that projects a fundus reflected image of the index onto a two-dimensional optical position sensor. The projection optical system has a first aperture that is substantially conjugate with the pupil of the eye to be examined, and the detection optical system is substantially conjugate with the pupil of the eye to be examined and has an eye fundus entrance on the pupil. a second aperture that spatially separates the light flux and the fundus reflected light flux, one of the first and second apertures being a single aperture;
The other type is characterized by a plurality of openings.

The gist of the second invention for achieving the above-mentioned object is to provide a projection optical system that projects an index provided on the optical axis onto the fundus of an eye to be examined, and a projection optical system that projects a reflected image of the fundus of the index onto a two-dimensional optical position sensor. The projection optical system has a central aperture on an optical axis that is substantially conjugate with the pupil of the eye to be examined, and the detection optical system has a detection optical system that is approximately conjugate with the pupil of the eye to be examined. It is characterized by having an aperture that is conjugate and includes a plurality of positions around the optical axis that spatially separates the fundus incident light flux and the fundus reflected light flux on the pupil.

A third aspect of the invention for achieving the above-mentioned object is provided with a projection optical system that projects an index onto the fundus of an eye to be examined, and a detection optical system that projects a fundus reflected image of the index onto a two-dimensional optical position sensor. It has an eye refractive power measuring system, and the projection optical system has a first lens substantially conjugate with the pupil of the eye to be examined.
The detection optical system includes a second aperture that is substantially conjugate with the pupil of the eye to be examined and spatially separates the fundus incident light flux and the fundus reflected light flux on the pupil, and One of the apertures is a single aperture, and the other is a plurality of apertures, and further includes a first projection optical system that projects a corneal shape measurement index onto the cornea of the eye to be examined; The present invention is characterized by comprising a second detection optical system that projects a reflected image onto the two-dimensional optical position sensor by sharing a part of the optical path of the first detection optical system.

[Embodiments of the invention]

The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows a first embodiment of the present invention, in which a lens 22 is provided along an optical axis 05 of a light beam emitted from a fundus illumination light source 21, and has a single aperture in the center and is generally conjugate to the pupil of the eye to be examined. Perforated mirror 2
3. Similarly, a diagonally installed light splitting member 24 is arranged,
The eye to be examined E is placed on the optical axis 06 on the reflection side of the light splitting member 24.
An objective lens 25 is arranged facing the. Around this objective lens 25, there are four point light sources 26a, 26b, 26c, 26 as shown in FIG.
d are arranged at equal angles with the optical axis 06 as the center. On the optical axis 06 behind the objective lens 25 and the light splitting member 24, there is an aperture 27 and an obliquely installed light coupling member 2.
8. Area sensor arrays 29 are arranged in sequence. Also, among the light emitted from the eye E, the light beam reflected in the optical axis 5 direction by the light splitting member 24 is placed on the optical axis 07 on the reflection side by the perforated mirror 23 as shown in FIG. 2b. A diaphragm 30, a lens 31, which has three radially arranged apertures 30a, 30b, and 30c, and is generally provided approximately conjugate to the pupil of the eye to be examined.
Three small wedge prisms 32a, 32 shown in FIG. 2c
A wedge prism 32 and an oblique deflection mirror 33 are arranged, and the light beam deflected by the deflection mirror 33 passes through the optical axis 08 to the optical coupling member 28.
The light is deflected in the direction of the optical axis 06 by the light beam, and is made incident on the area sensor array 29. Here, the fundus illumination light source 21 and the Eliasen array 29 are substantially conjugate with the fundus Er of the emmetropic eye E to be examined.

The light flux from the fundus illumination light source 21 passes through the lens 22 and the perforated mirror 23, is reflected by the light splitting member 24, and then passes through the pairing lens 25 to the fundus Er of the eye E to be examined.
reach. The fundus reflected light flux reflected by the fundus Er passes through the objective lens 25, is reflected by the light splitting member 24, is further reflected by the perforated mirror 23, passes through the diaphragm 30, the lens 31, the wedge prism 32, and further passes through the deflection mirror 33, The light is reflected by the optical coupling member 28 and reaches the area sensor array 29.

If the eye E to be examined is an emmetropic eye, the light beams emitted from the three apertures 30a, 30b, and 30c of the diaphragm 30 match on the area sensor array 29.
A wedge prism 32 is required to separate these and measure their respective positions. For example, aperture 3
The light beam emitted from the aperture 30a at 0 is deflected by the small wedge prism 32a and reaches a position 21A shown in FIG. 3a on the area sensor array 29. Similarly, the luminous flux emitted from the apertures 30b and 30c is 21
By measuring the positions of these light beams, the refraction values in the three radial directions can be determined, and from this, the refraction values of spherical refractive power, degree of astigmatism, and angle of astigmatism can be calculated. The principle of this measurement is described in Japanese Patent Laid-Open No. 59-64022. Further, the information on the positions of the light beams 21A, 21B, and 21C can be obtained not only in the radial direction but also in the direction perpendicular to the radial line, which increases the amount of information for determining the refraction value.

On the other hand, the light beam emitted from the corneal illumination light source 26 for corneal curvature measurement forms a virtual image of the light source on the cornea Ec,
It is imaged by the objective lens 25 onto the area sensor array 29 as shown in FIG. 3b. In FIG. 3b, four point light sources 26a, 26b, 26c, 26 are imaged on the area sensor array 29.
The images of d are 26A, 26B, 26C, and 26, respectively.
It is represented by D.

There is a proportional relationship between the size of the image shown in Figure 3b and the corneal curvature, so as the corneal curvature increases, the images become dispersed, and conversely, as the corneal curvature decreases, the images become concentrated. By measuring the position, the corneal curvature can be determined. If the cornea of the eye E
If Ec has astigmatism and the corneal curvature is different in the vertical and horizontal directions, image 26A in Fig. 3b,
The distance of 26C and the distances of 26B and 26D are different.

Also, if the astigmatism angle is oblique, the image 26A
Since the direction connecting 26B and 26B deviates from that of the light source, the degree of astigmatism and the angle of astigmatism can be determined from these amounts. In principle, there are three unknowns regarding the corneal refraction value: spherical power, astigmatic power, and astigmatic angle.If you include the central coordinates (x, y), there are five unknowns. These values can be calculated if the location is known.

In the above-described embodiments, the light splitting member may move a mirror to split the optical path, and it goes without saying that a shutter and a half mirror may be combined.

〔Effect of the invention〕

As explained above, according to the eye measurement device according to the present invention, a separated fundus reflection image is formed on the two-dimensional optical position detector without passing through a cylindrical lens, and the radial position information and the radial direction perpendicular direction are obtained. Eye refractive power information including astigmatism can be easily and accurately measured from position information.

[Brief explanation of drawings]

The drawings show an embodiment of the eye measurement device according to the present invention, and FIG. 1 is a configuration diagram of the first embodiment, and FIGS. 2a, b, and c are used in the first embodiment. The front view of the member and FIGS. 3a and 3b are illustrations of the bottom reflected light beam and the corneal reflected light beam on the area sensor array, respectively. Reference numeral 21 is a fundus illumination light source, 27 and 30 are apertures,
23 is a perforated mirror, 24 is a light splitting member, 25 is an objective lens, 26 is a corneal illumination light source, 32 is a wedge prism, 28 is a light coupling member, and 29 is an area sensor array.

Claims (1)

[Scope of Claims] 1. An eye refractive power measurement system that includes a projection optical system that projects an index onto the fundus of an eye to be examined, and a detection optical system that projects a fundus reflected image of the index onto a two-dimensional optical position sensor. The projection optical system includes a first aperture that is substantially conjugate to the pupil of the eye to be examined, and the detection optical system is substantially conjugate to the pupil of the eye to be examined and spatially separates the fundus incident light flux and the fundus reflected light flux on the pupil. a second opening that is separated from each other; one of the first and second openings is a single opening;
An eye measurement device characterized in that the other is a plurality of apertures. 2. An eye refractive power measurement system comprising a projection optical system that projects an index provided on the optical axis onto the fundus of the eye to be examined, and a detection optical system that projects the fundus reflected image of the index onto a two-dimensional optical position sensor. The projection optical system has a central aperture on an optical axis that is substantially conjugate with the pupil of the eye to be examined, and the detection optical system is substantially conjugate with the pupil of the eye to be examined and allows the incident light beam of the fundus and the reflected light beam of the fundus to separate on the pupil. An eye measurement device characterized by comprising an aperture including a plurality of positions around an optical axis that spatially separate the images. 3. The eye measurement device according to claim 2, wherein the detection optical system includes a cylindrical lens that condenses a light beam incident on the two-dimensional optical position sensor. 4. An eye refractive power measurement system including a projection optical system that projects an index onto the fundus of the eye to be examined and a detection optical system that projects a fundus reflected image of the index onto a two-dimensional optical position sensor, the projection optical system comprising: The first pupil is approximately conjugate to the pupil of the eye to be examined.
The detection optical system includes a second aperture that is substantially conjugate with the pupil of the eye to be examined and spatially separates the fundus incident light flux and the fundus reflected light flux on the pupil, and One of the apertures is a single aperture, and the other is a plurality of apertures, and further includes a first projection optical system that projects a corneal shape measurement index onto the cornea of the eye to be examined; An eye measurement device comprising: a second detection optical system that projects a reflected image onto the two-dimensional optical position sensor by sharing a part of the optical path of the first detection optical system. 5. The eye measuring device according to claim 4, wherein the light beam for measuring eye refractive power and the light beam for measuring corneal shape have different wavelengths, and the optical paths of both light beams are combined by a dichroic mirror. 6. The eye measuring device according to claim 4, wherein the optical path of the eye refractive power measurement light beam and the corneal shape measurement light beam can be selected by inserting and removing a movable mirror into the optical path.