JP2001112715A - Eye examination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance measuring accuracy by facilitating alignment, and preventing errors caused by distance. SOLUTION: Light sources 2, 3 each comprise a plurality of LEDs arranged on a printed circuit board 1 in such a manner as to form a plurality of concentric rings with different diameters, with the LEDs of each ring being approximately equally spaced apart in such a manner that the radial spacing therebetween is greater than the circumferential spacing therebetween. A ring- shaped light conducting member is positioned near the circumference of the printed circuit board 1. Light source images 2', 3', 5' produced by illuminating light coming from the light sources 2, 3 and the light conducting member 5 are formed on an area sensor 25 and displayed on a display monitor 25. Four analysis of the shape of a cornea, the position of each LED is recognized and the circumferential curvature of the cornea is determined from the spacing between the images on the same ring. The LED images on the same ring are recognized as rings, and the radial curvature of the cornea is determined from the radial distance between the rings. The circumferential and radial curvatures are averaged to determine the curvature of each part of the cornea.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometric apparatus used in an ophthalmic hospital or an optician.

[0002]

2. Description of the Related Art Conventionally, there is a corneal shape measuring device for measuring a corneal shape by imaging a large number of point-like light source images, and a special device for projecting a light beam with parallel light or performing measurement with parallel reflected light. A corneal shape measuring apparatus provided with a simple optical system is known.

[0003]

However, the above-mentioned conventional optometry apparatus requires a space in the optical axis direction because the optotype is illuminated by a light source arranged at a distant position. Since the measurement is performed after the distance is accurately adjusted so as not to cause the problem, there is a problem that the operation is complicated.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an optometry apparatus which can easily perform positioning and has improved measurement accuracy by preventing errors due to distance.

It is another object of the present invention to provide an optometric apparatus which can measure a curvature in a circumferential direction in addition to a radiation direction of a cornea with a simple configuration without using a special optical system.

[0006]

An optometry apparatus according to the present invention for achieving the above object has a light source for projecting a light beam on a cornea, and an imaging means for imaging a corneal reflection image by the light source. In an optometry apparatus that measures a corneal shape using a corneal reflection image, a plurality of point-like light sources are provided around the measurement optical axis, the positions of these light sources are stored for each device, and the stored position information is used. The corneal shape is measured.

An optometry apparatus according to the present invention has a light source for projecting a light beam on the cornea, and an imaging means for imaging a corneal reflection image by the light source, and measures a corneal shape using the corneal reflection image. The optometry apparatus is characterized in that a plurality of point-like light sources provided around the measurement optical axis and a mask member having a light transmitting portion corresponding to each light source are provided in the vicinity of these light sources.

An optometry apparatus according to the present invention includes a light source for projecting a light beam onto the cornea, and an imaging unit for capturing a corneal reflection image by the light source, and measures a corneal shape using the corneal reflection image. A corneal shape measurement light source provided around the measurement optical system, a corneal shape measurement light source having a different wavelength from the corneal shape measurement light source, and a luminous flux from the corneal shape measurement light source is not transmitted and the position measurement is performed. A corneal reflection image of the position measurement light source is separated and formed into a central portion of a corneal reflection image of the corneal shape measurement light source through two optical paths that transmit a light flux from the light source for the two. A corneal shape is measured by projecting a corneal reflection image together with the image pickup means, storing and calculating these video signals.

An optometry apparatus according to the present invention includes a light source for projecting a light beam from a light source onto a cornea, and an area array sensor for detecting a corneal reflection image from the light source, and measures a corneal shape using the corneal reflection image. In the optometry apparatus, the light source is configured by arranging a plurality of point-like light sources in a plurality of concentric circles having different sizes, and setting a radial interval of each circumference of a corneal reflection image of the light source to an adjacent row. It is characterized in that it is wider than the interval between the light source images on the circumference.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 shows a configuration diagram of an optometry apparatus according to an embodiment, which is an apparatus having an auto-refractometer, an auto-keratometer, and a corneal shape measurement function. A corneal illumination optical system is arranged on the eye E side of the apparatus, and the corneal illumination optical system is provided on a disc-shaped printed circuit board 1 as shown in FIG. A plurality of red LED light sources 2 and 3 for radius measurement are attached, and a disk-shaped cover member 4 for transmitting the light flux of these light sources 2 and 3 on the front surface, and a cylindrical ring surrounding the cover member 4 The light guide member 5 is arranged.

The printed board 1 of the corneal illumination optical system is provided with a circular opening 6 at the center through which a measurement light beam passes, and two arcuate openings 7 at both sides through which a position detection light beam passes. The light sources 2 and 3 are arranged around the aperture 6 in multiple concentric circles, for example, in six rows of rings, and one row, two rows,
The fourth, fifth, and sixth rows are light sources 2, and the third row is a light source 3 for measuring a corneal curvature diameter. These light sources 2 and 3 are provided with a plurality of light sources such that ring-shaped corneal reflection images are generated at substantially equal intervals.
A plurality of concentric EDs are arranged in a ring shape having different diameters toward the cornea of the eye E to be examined.
The intervals between the EDs are substantially equal, and the intervals in the radial direction are arranged to be larger than the intervals in the circumferential direction of the adjacent rows. The luminous flux from the outermost light source 2 directly illuminates the cornea and illuminates the cornea via the light guide member 5.

The light guide member 5 is provided along the outer periphery of the cover member 4 and is made of a short-cylindrical member such as an acrylic resin that transmits light, and a light beam incident from an end face of the light guide member 5 on the light source 2 side. Are reflected on the inner surface and guided to the end surface on the eye E side. A reflection surface is formed on the end surface on the side of the subject's eye E, and the guided light flux is reflected by the reflection surface to become a target projected on the cornea, and the reflection image from the cornea is formed as a ring image. It is displayed.

On the measurement optical path O1 in front of the eye E, behind the opening 6 of the corneal illumination optical system, the light splitting member 8, the lens 9, the light splitting member 10, and the lens 9 together with the anterior segment of the eye E. Lens 11 for imaging an image, imaging means 1 as a video camera
2 are sequentially arranged. On the optical path O3 in the incident direction of the light splitting member 10, a mirror 13, a diopter variable lens 14 movable in the optical path direction, and a fixation target 15 are arranged.

A lens 1 having a smaller diameter than the lens 9 is placed on the optical path O2 of the refraction measuring optical path in the incident direction of the light splitting member 8.
6, a mirror 17, a perforated mirror 18, a central aperture stop 19 conjugated to the pupil, a lens 20, a red conjugated to the ocular fundus of a different wavelength from the light source 3 for use in refraction measurement and position measurement of the eye E to be examined. Outside LED light sources 21 are arranged. In the reflection direction of the perforated mirror 18, there are arranged a peripheral aperture stop 22 conjugate to the pupil, a light deflecting member 23 for deflecting the light beam out of the optical path, a lens 24, and an area array sensor 25 such as a CCD conjugate to the ocular fundus. I have. The outputs of the imaging unit 12 and the area sensor 25 are calculated by the arithmetic unit 26 and the display monitor 27.
Connected to each other.

FIG. 3 is a front view of the light splitting member 8. A thin film that reflects light of the wavelength of the light source 21 and transmits light of the wavelengths of the light sources 2 and 3 is provided on a central portion 8 a of the light splitting member 8. I have. The size of the central portion 8a is determined by the size of the central opening 6 of the printed circuit board 1.
, And a wedge glass 8b is adhered to both sides thereof. Light source 2 for wedge glass 8b
An optical thin film that transmits light of one wavelength and does not transmit light of wavelengths of the light sources 2 and 3 is provided. A light beam passing through the opening 7 of the printed circuit board 1 passes through the wedge glass 8b.

With such a configuration, the fixation target 15 is projected onto the eye E through the diopter variable lens 14. At the time of positioning, the anterior segment moving image projected by the imaging means 12 is displayed on the display monitor 27, and positioning is performed. At the time of corneal measurement, the video signal of the imaging means 12 is taken into the calculating means 26 and the corneal shape is calculated. Further, at the time of refraction measurement, the signal of the area array sensor 25 is taken into the calculating means 26 and the refraction value is calculated.

At the time of positioning and measurement of the corneal shape measurement, the light source 21 is turned on together with the light sources 2 and 3. As shown in FIG. 1, an anterior segment image E ′ and light source images 2 ′, 3 ′, 5 ′, and 21 ′ of these light sources are displayed on the display monitor 27. The images of the light sources 2 and 3 due to corneal reflection pass through the aperture 6 and the central portion 8a of the light splitting member 8 and pass through the lenses 9 and 11 to the imaging means 12
The image is formed on the display monitor 27 as shown in FIG.
Will be displayed. The light source images 2 ', 3', and 5 'are formed in substantially equally-spaced ring shapes. Since the light source 21 is on the extension of the optical path O1, a reflection image 21' is formed at the center of the cornea.

The corneal reflection image 21 ′ is deflected through the two apertures 7 and the wedge glass 8 b of the light splitting member 8, and is slightly separated vertically in a direction perpendicular to the direction connecting the two apertures 7. An image 21 'is formed at the center of the light source image 2'.
The distance to the eye E is adjusted so that the two corneal reflection images 21 'are located at the same position in the horizontal direction and are arranged vertically.

At the time of measurement, the image showing the corneal reflection image 21 'together with the light source images 2', 3 'and 5' is taken into the calculating means 26, and the distance at the time of measurement is recorded. Two corneal reflection images 2
The light source 21 in the eye E to be inspected from the apparatus based on the lateral displacement amount 1 ′
Since the distance to the virtual image of corneal reflection is known, the corneal curvature having a diameter of about 3 mm at the central part of the cornea is assumed to be spherical using the light source image 3 ′ of the light source 3, and numerical calculation is performed to calculate the corneal reflection image 21 ′. The corneal curvature radius is measured from the distance. First, assuming that the radius of curvature is 7.8 mm, which is an average value, the distance L1 to the corneal vertex can be assumed from this. Therefore, the radius of curvature r1 is calculated using this distance and the size of the light source image 3 ′. .
Next, the radius of curvature r2 is determined by assuming the distance L2 to the corneal vertex using the radius of curvature r1 instead of 7.8 mm. As this calculation is repeated, the radius of curvature gradually approaches the true radius of curvature r and the true vertex distance L. However, in practice, a sufficient accuracy can be obtained by repeating a few times.

The radius of curvature and the vertex distance calculated as described above,
The shape of another corneal part is calculated from the positions of the captured light source images 2 ′, 3 ′, and 5 ′ and their mutual distances. The corneal reflection image 21 'for distance measurement has information on the shape of the central portion of the cornea and is generated at the center of the cornea.
The midpoint of the two corneal reflection images 21 ′ is at the center of the light source image 2 ′ in a normal cornea, but the shape of the central portion of the cornea is analyzed using information such as deviation from the center when the corneal vertex is decentered. .

At the time of manufacture, the position of each LED of the light sources 2 and 3 is obtained using the image of the image pickup means 12 based on the reference sphere arranged at a predetermined position for each device and stored in the arithmetic means 26. In the measurement of the cornea, a measurement calculation is performed using the stored calibration values. As a result, accurate measurement can be performed irrespective of variations at the time of mounting each LED, and it is not necessary to strictly adjust the position of each LED at the time of manufacturing, thereby enabling labor saving.

Since the corneal curvature radius is often measured simultaneously with the refraction measurement, the corneal measurement light source 3 in this case is preferably measured with infrared light so as not to affect the refraction measurement. In this case, the light source 2 is turned off and the light source 3 is turned on, and the light source 21 is used for position detection and refraction measurement. At the time of corneal curvature measurement, the images 3 'and 21' reflected on the imaging means 12 are simultaneously stored,
The curvature is calculated from these. Imaging means 1 for refraction measurement
2 'and 3', 21 'and area array sensor 25
The reflected fundus of the light source 21 reflected by the light source 21 is simultaneously stored in the calculating means 26, and an accurate refraction value is obtained using the distance to the corneal reflection image 21 '.

Since the iris reflectance of visible light is relatively low, when the light source 2 is made to be visible light, the contrast of the light source image 2 'is increased, and accurate detection can be performed. On the other hand, it is necessary to confirm the pupil at the time of corneal shape measurement or refraction measurement, and the pupil can be easily recognized by setting the light source 3 to infrared light that reflects the iris strongly.

The ring-shaped light sources 2 and 3 having different diameters are arranged such that the LED spacing of each ring is substantially equal and the radial spacing is greater than the circumferential spacing of the adjacent rows, so that the LED image is formed. Can be clearly recognized as a ring image and will not be confused with the LED images of other ring arrays.

In the analysis of the corneal shape, the position of each LED is recognized, and the circumferential curvature of that portion of the cornea is determined from the image interval of the same ring row. LED on the same ring
The image is recognized as rings, and the radial curvature of the cornea is determined from the radial distance between the rings. Then, the curvature in each part of the cornea is obtained by averaging the curvatures in the circumferential direction and the radial direction.

FIG. 4 is a side view of a corneal illumination optical system according to another embodiment. The cover member 4 in FIG. 1 is replaced by a diffusion plate 28 and a mask member 29. The diffuser plate 28 is provided with an opening of the same shape at a portion corresponding to the opening 7 of the printed circuit board 1, and the mask member 29 has a circular light transmitting portion at the portion corresponding to each LED of the light sources 2 and 3, and an opening. A light transmitting portion having the same shape is provided in a portion corresponding to 7. Then, the diffusion member 27 and the mask member 29 are arranged close to the light sources 2 and 3.

[0027]

As described above, in the optometry apparatus according to the present invention, a plurality of point-like light sources are provided around the measuring optical path, their positions are stored for each apparatus, and the stored position information is used. By measuring the shape of the cornea, the target projection optical system can be shortened in the optical path direction and the configuration can be simplified,
At the same time, the corneal curvature in the circumferential direction can be measured, and the measurement accuracy can be improved.

An optometry apparatus according to the present invention provides a mask including a plurality of point-like light sources provided around a measurement optical path, and a light transmitting portion corresponding to each of the light sources in proximity to the light sources. By providing the member, the target projection optical system can be shortened in the optical path direction and the configuration can be simplified,
At the same time, the corneal curvature in the circumferential direction can be measured, and the measurement accuracy can be improved.

The optometry apparatus according to the present invention has two optical paths that transmit the position measurement light without transmitting the corneal shape measurement light.
The corneal reflection image of the position light source is separated and formed at the center of the corneal reflection image of the corneal shape measurement light source, and the corneal reflection image of both light sources is stored, and the image signal of the imaging means is stored and the corneal reflection is calculated. By measuring the shape, a special optical system for projecting parallel light and measuring with parallel reflected light is not used, so that the configuration can be simplified, and at the same time, simple positioning is possible and errors due to distances occur. Never.

In the optometry apparatus according to the present invention, the light sources are arranged such that point-like light sources are arranged on a plurality of concentric circles having different sizes, and the circumferential intervals of the corneal reflection images of these light sources are adjacent to each other. By making the interval between the point light source images on the circumference wider, it becomes possible to measure the curvature in the circumferential direction in addition to the radiation direction of the cornea.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optometry apparatus according to an embodiment.

FIG. 2 is a front view of a corneal illumination optical system.

FIG. 3 is a front view of a light splitting member.

FIG. 4 is a side view of another corneal illumination optical system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2, 3, 21 Infrared LED light source 4 Cover member 5 Light guide member 8, 10 Light division member 12 Imaging means 15 Fixation target 18 Perforated mirror 19 Center aperture stop 22 Peripheral aperture stop 23 Light deflection member 25 Area array sensor 26 Calculation means 27 Display monitor 28 Diffuser 29 Mask member

Claims (4)

[Claims] 1. An optometric apparatus, comprising: a light source that projects a light beam onto a cornea; and an imaging unit that captures a corneal reflection image by the light source, wherein the corneal shape is measured using the corneal reflection image.
An optometry apparatus comprising: a plurality of point-like light sources provided around a measurement optical axis; the positions of these light sources are stored for each device; and the corneal shape is measured using the stored position information. 2. An optometric apparatus comprising: a light source for projecting a light beam onto a cornea; and an imaging unit for imaging a corneal reflection image by the light source, wherein an corneal shape is measured using the corneal reflection image.
An optometric apparatus, comprising: a plurality of point-like light sources provided around a measurement optical axis; and a mask member having a light transmitting portion corresponding to each light source in close proximity to these light sources. 3. An optometric apparatus comprising: a light source for projecting a light beam onto a cornea; and an imaging unit for capturing a corneal reflection image by the light source, wherein the corneal shape is measured using the corneal reflection image.
A corneal shape measurement light source provided around the measurement optical system, and a corneal shape measurement light source and a position measurement light source having a different wavelength,
Through two optical paths that do not transmit the light beam from the corneal shape measurement light source but transmit the light beam from the position measurement light source,
The corneal reflection image of the position measurement light source is separated and formed at the center of the corneal reflection image of the corneal shape measurement light source, and both the corneal reflection images of the light sources are projected on the imaging means, and these images are displayed. An optometric apparatus characterized in that a corneal shape is measured by storing and calculating a signal. 4. An optometric apparatus, comprising: a light source for projecting a light beam of a light source onto a cornea; and an area array sensor for detecting a corneal reflection image by the light source, wherein the corneal shape is measured using the corneal reflection image. The light source is composed of a plurality of point light sources arranged in a plurality of concentric circles of different sizes, and a light source image on the circumference of a row adjacent to the corneal reflection image of the light source at a radial interval of each circumference. An optometric apparatus characterized in that the interval is wider than the interval between the two.