JPH05269084A - Optometrical apparatus - Google Patents

Abstract

PURPOSE:To determine a formula for the optimum size of a contact lens and a base curve. CONSTITUTION:An image of an eye to be inspected reaches a TV camera 14 via an optical path 02 and an infrared source 21 for alignment lighting, a light source 27 for measuring the diameter of the iris and an infrared cut filter 28 are arranged at positions away from the optical path 02 in front of a dichroic mirror 7. An output of a TV monitor 15 is connected to the TV camera 14 to allow the observation of the anterior ocular segment. When light is emitted from the infrared source 21 to complete an alignment, the light source 27 is made to emit light to light an eye E to be inspected by visible light. The reflected light from the eve to be inspected reaches the TV camera 14 via the optical path 02 to take an image of the anterior ocular part. The diameter of the iris is calculated depending on an intensity level of a scan line at the center from the anterior ocular part image thereby determine the diameter 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 optometry apparatus widely used in ophthalmology clinics and the like.

[0002]

2. Description of the Related Art In order to prescribe a contact lens, the measurement of the corneal diameter and the measurement of the corneal curvature are indispensable for determining the diameter and the base curve of the contact lens to be prescribed. Conventionally, the corneal diameter is measured by projecting the anterior segment image illuminated by infrared light on the anterior segment observation TV monitor for a keratometer, visually inspected by an examiner, and roughly using a scale on the TV monitor. The iris diameter is measured and the corneal diameter is calculated from the obtained iris diameter. Further, the corneal curvature can be calculated by measuring the central part of the cornea and a part of the peripheral part.

[0003]

However, it is difficult to clearly determine the boundary of the iris with infrared light, and an accurate iris diameter cannot be obtained by visual measurement. Furthermore,
In the corneal curvature measurement, there are problems that the cornea cannot be measured in a necessary and sufficient range, and that the curvature measurement in the radial direction, the meridional direction, is insufficient.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an optometry device that enables optimal prescription of contact lenses.

[0005]

The eye examination apparatus according to the first aspect of the present invention for achieving the above object is an illumination apparatus for illuminating an anterior eye portion with visible light in an eye examination apparatus capable of imaging an anterior eye portion by an image pickup device. Means and means for measuring the iris diameter from the signal of an appropriate scanning line of the anterior segment image by the imaging device.

Further, an eye examination apparatus according to a second aspect of the present invention for achieving the above object is an illumination system for projecting a light flux onto a cornea of an eye to be examined from an optical axis direction and a peripheral direction including a plurality of radial lines, and a cornea of the light flux. A light receiving system for receiving the reflected light flux in the optical position detection sensor, an alignment system having an alignment mark on the optical axis, and a corneal peripheral measurement fixation target provided around the optical axis, the optical axis direction Is measured in accordance with the alignment mark, and the shape of the cornea is obtained from the position of the cornea reflected light beam of the illumination system light beam.

[0007]

In the optometry apparatus according to the first aspect of the present invention having the above-mentioned structure, the anterior segment of the eye is illuminated with visible light for imaging, and the measuring means analyzes the signal intensity of an appropriate scanning line of the imaging signal to calculate the iris diameter. To do. The eye examination apparatus according to the second invention illuminates the eye to be examined by an illumination system with the line of sight of the subject facing the alignment mark, analyzes the reflected light in the light receiving system to obtain the curvature of the center of the cornea, and then fixes the eye. The line of sight of the subject is sequentially guided to the target, and the corneal curvature of the peripheral portion is measured.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a block diagram of a combination of the eye refraction measuring device, the corneal curvature radius measuring device, and the iris diameter measuring device according to the first embodiment. On the optical path 01 from the light source 1 of the refraction measuring device to the eye E, a lens 2, a diaphragm 3, a perforated mirror 4,
A mirror 5, a lens 6, and a dichroic mirror 7 are sequentially arranged. On the optical path 02 behind the dichroic mirror 7 as seen from the eye E, there are a lens 8, a half mirror 9, an aperture stop 10 provided at the back focal position of the lens 8, a lens 11, a dichroic mirror 12, and an image sensor 13. The TV cameras 14 are arranged. Further, the image information of the television camera 14 is output to the television monitor 15 via a processing device (not shown). Between the perforated mirror 4 and the dichroic mirror 12, a six-hole diaphragm 16 having six holes provided in axial symmetry, a lens 17, and a wedge divided into six to correspond to the six holes of the six-hole diaphragm 16. A separation prism 18 composed of prisms is arranged. Further, in the reflecting direction of the half mirror 9, an index 19 for guiding the line of sight of the subject and a diopter lens 20 thereof are provided.

An optical system for cornea measurement is arranged in front of the eye E to be inspected, and the infrared light source 21 is a light source for alignment of the eye to be inspected. Further, a diaphragm 23 is arranged on the optical path 03 from the light source 22 to the subject's eye E, and the reflected light thereof reaches the light receiving element 25 via the diaphragm 24.
Further, a total of four light sources 26 are arranged in the vicinity of the diaphragms 23 and 24 in axial symmetry with respect to the optical path 01. Further, a light source 27 for measuring cornea diameter and an infrared cut filter 28 are provided obliquely above the eye E to be examined. It is arranged so that visible light is projected onto the eye E to be inspected.

FIG. 2 is a signal block diagram. The signal processor 30 including a CPU is connected to the television camera 14, a mode selecting means 31 for selecting a measuring method, and a joystick 32. The examiner selects the mode selection means 31,
When the joystick 32 is pressed, the signal of the TV camera 14 is processed by the signal processor 30 according to the selected measurement method.

At the time of eye refraction measurement, alignment is first performed with respect to the eye E to be examined, and the subject is made to gaze at the optotype 19. When the examiner pushes the joystick 32, the light source 1 emits light, and the infrared light flux passes through the optical path 01 and reaches the eye E to be inspected. The fundus reflected light travels backward in the optical path 01, and the perforated mirror 4
Is reflected by the dichroic mirror 12, passes through the 6-hole diaphragm 16, the lens 17, and the separating prism 18, and is received by the image pickup device 13. Six spot images are projected on the image sensor 13, and their positions are related to the eye refractive power. Therefore, the eye refraction value is calculated by analyzing the positions of these six spot images by the signal processor 30.

When measuring the corneal curvature, the light source 22 is turned on to illuminate the anterior segment of the eye E to be examined. When the eye E to be inspected is in the alignment state, the signal of the light receiving element 25 becomes maximum and the four light sources 26 automatically emit light. The corneal reflected light enters the television camera 14 via the optical path 02, and the corneal curvature is calculated from the position of the corneal reflected image.

At the time of measuring the iris diameter, the alignment is confirmed by the light flux of the infrared light source 21, and when the alignment is completed, the light source 27 is caused to emit light, and the anterior ocular segment reflected light is received by the television camera 14. Of the signals from the television camera 14, the intensity of one scanning line S corresponding to the center of the subject's eye is shown in FIG.
As shown in. That is, since the iris portion Ei has strong absorption of visible light, a rectangular intensity distribution is generated, and the boundary between the iris portion Ei and the white scleral portion Ek appears clearly. The signal of the scanning line S is analyzed by the signal processor 30 to obtain the cornea diameter. Since the light source 27 illuminates the subject's eye E from above, the corneal reflected light does not interfere with the measurement. Further, instead of separately providing the light source 27, an infrared filter and a visible filter may be detachable from the infrared light source 21.

FIG. 4 is a block diagram of the second embodiment. In the optical path 04 in front of the eye E to be inspected, the half mirror 34 and the television camera 14 for eye observation are provided separately from the eye refraction measurement. A system 35 is provided, and in the reflection direction of the half mirror 34,
A lens 36, a diaphragm 37 arranged at the back focal position of the lens 36, and a television camera 14 are arranged. The light source 26 used in the first embodiment is replaced with a set of a light source 38 and a collimator lens 39 for collimating the light flux thereof. In this embodiment, since the diaphragm 37 is provided, the measurement error due to the working distance is small when measuring the corneal diameter.

FIG. 5 is a third embodiment of an autorefkeratometer.
It is a block diagram of the Example of. A lens 42, a diaphragm 43, a perforated mirror 44 having a central opening 44a, a lens 45, and a dichroic mirror 46 are arranged in an optical path O5 from the refraction measuring light source 41 to the eye E. A lens 47, a dichroic mirror 48, an adjustable diopter adjustment lens 49, and a target 50 are provided in the reflection direction of the dichroic mirror 46, and a lens 51, a dichroic mirror are provided in an optical path O6 in the reflection direction of the dichroic mirror 48. 52, a diaphragm 54 that is detachably provided in the optical path by a driving device 53, and a television camera 55. The output of the TV camera 55 is connected to the TV monitor 56.

Between the perforated mirror 44 and the dichroic mirror 52, there are provided a six-hole diaphragm 57 having six holes, a lens 58, and a separation prism 59 which is a combination of six wedge prisms. Between the dichroic mirror 46 and the eye E, four light sources 60 symmetrically with respect to the optical path O5, and four fixed target light sources 61, and each fixed target light source 6 are provided.
A diaphragm 62 corresponding to 1 is provided. In addition, diaphragm 6
2 may be provided with a lens. Further, two anterior ocular segment illumination light sources 63 are provided on the left and right, and are arranged as shown in FIG.

Alignment is performed while the subject is looking directly at the optotype 50. When the light source 41 is turned on during refraction measurement, the light flux reaches the eye E through the optical path O5. The fundus reflected light returns to the optical path O5 again, is reflected by the perforated mirror 44, passes through the 6-hole diaphragm 62, the lens 58, the separating prism 59, and the dichroic mirror 52, and then the television camera 5.
Image on 5. On the television camera 55, as shown in FIG. 7, six spot images 62 'generated by the six holes of the six-hole diaphragm 62 and a light beam 41' partially reflected by the dichroic mirror 46 and passing through the optical path O6 are received. Has been done. The eye refractive power is analyzed and calculated by the signal processor (not shown) at the positions of the six spot images 62 '.

At the time of measuring the corneal curvature, the anterior ocular segment illumination light source 63 is turned on, and the alignment is performed while checking the image of the eye to be inspected on the television monitor 56 as shown in FIG. Eye E
Is placed at a predetermined position, the driving device 53 is driven by pushing a measurement switch (not shown), the diaphragm 54 is inserted into the optical path O6, the depth of focus becomes deep, and the measurement accuracy improves. The anterior ocular segment illumination light source 63 is turned off in an instant, and the four light sources 60 are turned on instead. The magnitude of the corneal curvature is determined by the four images 6 of the light source 60 received by the television camera 55.
The three points of 0'are obtained, and the curvature and the astigmatic angle on the principal radial line are calculated by the method of approximating the astigmatic corneal center to the toric surface from the major and minor axis lengths and angles of the ellipse passing through these three points. Theoretically, the same result should be obtained regardless of which three points are taken, but it is preferable to average the results of all patterns because an error occurs due to approximation.

When the curvature of the central part of the cornea is measured, 4
The one fixed target light source 61 is sequentially turned on. The subject moves his or her line of sight to the fixed target light source 61 that is sequentially turned on. With the line of sight directed toward a certain fixed target light source 61, the light source 60 is turned on as shown in FIG. 9 to measure the curvature. In FIG. 9, the light source image and the peripheral image at the center of the cornea are shown at the same time.
Actually, they are not observed at the same time. By measuring the curvature of the central part of the cornea and the curvature of the four peripheral parts, the radius of curvature in the radial direction of the cornea can also be measured.

FIG. 10 is a block diagram of the fourth embodiment. For the sake of convenience, the same members as those in the third embodiment are designated by the same reference numerals and the description thereof will be omitted. However, the television camera 55 is used for anterior ocular segment observation and keratometer measurement. The dichroic mirror 6 is provided in the optical path O7 from the light source 66 to the eye E to be inspected.
7, diopter adjustment lens 49 movable in the optical path direction, dichroic mirror 68, lens 69, dichroic mirror 7
0, a ring light source 71 having the optical path O7 as a central axis is provided. An optotype 50 is provided behind the dichroic mirror 67, and a refractometer unit 72 having all the functions of a refractometer is provided behind the dichroic mirror 70. Further, behind the dichroic mirror 68, a lens 73, a diaphragm 54 driven by the driving device 53, and a television camera 55 are sequentially arranged.

At the time of measurement, the ring light source 71 is turned on, and alignment is performed while the subject is fixed on the visual target 50. When the alignment is completed, the curvature of the central part of the cornea is measured.
FIG. 11 shows an image of the cornea Ec taken by the television camera 55. An image 71 'of the ring light source 71 and an image 66' of the light source 66 are observed on the cornea Ec. The corneal curvature is the horizontal line Lh passing through the image 66 'and its vertical line Lb intersects with the image 71'.
It is calculated from the diameter of the vertical line Lb of the ellipse passing through the points. In addition, the meridional radius of curvature around the cornea can be similarly obtained by turning on a fixed target (not shown) and guiding the line of sight.

[0022]

As described above, the optometry apparatus according to the first invention can calculate the iris diameter, and the optometry apparatus according to the second invention can calculate the diameter of the cornea and the curvature in the radial direction. Can be prescribed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a signal block diagram.

FIG. 3 is an intensity distribution by scanning lines.

FIG. 4 is a configuration diagram of a second embodiment.

FIG. 5 is a configuration diagram of a third embodiment.

FIG. 6 is a front view of an eyepiece of an eye to be inspected according to a third embodiment.

FIG. 7 is an explanatory diagram of a television camera light receiving state.

FIG. 8 is an explanatory diagram of a television monitor.

FIG. 9 is an explanatory diagram of a corneal reflection image.

FIG. 10 is a configuration diagram of a fourth embodiment.

FIG. 11 is a front view of a cornea Ec.

[Explanation of symbols]

1, 22, 26, 27, 41, 60, 66 Light source 4, 44 Perforated mirror 7, 12, 46, 48, 52, 67, 68 Dichroic mirror 14, 55 TV camera 21 Infrared light source 25 Light receiving element 28 Infrared Cut filter 50 Target 61 Fixed target light source 71 Ring light source 72 Refractometer unit

Claims (2)

[Claims] 1. An optometry apparatus capable of capturing an anterior segment with an image sensor, the illumination unit illuminating the anterior segment with visible light,
An optometry apparatus comprising: a measuring unit that measures an iris diameter from a signal of an appropriate scanning line of an anterior segment image by the image pickup device. 2. An illumination system for projecting a light flux onto the cornea of an eye to be examined from an optical axis direction and a peripheral direction including a plurality of radial lines, a light receiving system for receiving a corneal reflected light flux of the light flux on an optical position detection sensor, and the optical axis. An alignment system having an alignment mark on the top and a fixation target for corneal periphery measurement provided around the optical axis, and measuring the corneal reflection image in the optical axis direction in alignment with the alignment mark, and the illumination system An optometry apparatus for obtaining a corneal shape from a corneal reflection luminous flux position of a luminous flux.