JPH07323007A - Ophthalmic apparatus - Google Patents

Abstract

PURPOSE:To adjust easily and accurately an alignment with an extremely simple constitution by an subject himself by an apparatus wherein a standard mark and a fixed visual mark are laminated and observed by an eye to be inspected and a target mark is projected to judge whether the working distance is appropriate and it is judged based on the detected result. CONSTITUTION:A holding member 7 on which an concave mirror 6 is held is mounted on an apparatus, the mode is switched to a mode for a subject by an operator selecting switch. Under this condition, the subject holds the apparatus by one hand and put on an electric source switch to turn on each light source and determines the left and the right of a selected eye by means of an R/L switch. Then, an opening part 3 of a measuring window is positioned on the front of the selected eye to be inspected. When the eye 1 to be inspected watches the opening part 3, the end part 3' of the opening part 3 through the concave mirror 6 and the fixed visual mark 14' illuminated by a light source 13 is observed. Adjustment of alignment in upward, downward, left and right directions by using the opening end part 3' and the solid visual mark 14' is performed and then, adjustment on the working distance is performed.

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 measuring an eye to be inspected, and more particularly to a mechanism for aligning the eye to be inspected and the apparatus in a predetermined positional relationship.

[0002]

2. Description of the Related Art Alignment adjustment of an ophthalmologic apparatus usually involves adjusting the position of an eye such as the measurement optical axis of the apparatus and the eye to be inspected and adjusting the working distance from the eye to be inspected. In recent years, with the development of electronic technology, automated ophthalmologic apparatuses have been put into practical use, the operation of these apparatuses has been simplified, and measurement and the like can be easily performed without requiring skill.

However, automation in an ophthalmologic apparatus is mainly related to a part directly related to measurement. Of course, an apparatus for automating alignment has been proposed, but it has a drawback that the mechanism becomes complicated and the entire apparatus becomes large. Therefore, most of the devices for alignment adjustment still use the traditional mechanism.

According to such an alignment method, the inspector is obliged to perform the alignment, and the meaning of automating the measurement is halved. Therefore, a device has been proposed in which the subject can see the anterior segment image when the subject's eye is located at a predetermined working distance of the device.

[0005]

The above-described method in which the subject himself or herself visually recognizes and aligns the anterior segment image does not require an inspector, but the determination of the quality of the clear state is performed by the subject. It is difficult for a person, especially when the subject's eye has a refractive error.

[0006] Therefore, an object of the present invention is to provide an ophthalmologic apparatus which has an extremely simple structure and which allows a subject himself to easily and accurately perform alignment adjustment.

[0007]

In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) In an ophthalmologic apparatus having a measurement system for measuring an eye to be inspected, a projection optical system for projecting a fixation target on the eye to be inspected, and mark means for forming a reference mark as a reference for alignment. , A fixation target / mark superposition optical system for superimposing the reference mark on the fixation target and observing the eye to be inspected, and an index optical system for projecting and detecting an index for determining suitability of the working distance And a determination unit that determines whether the working distance is appropriate based on the detection result of the index optical system.

(2) The ophthalmologic apparatus of (1) is provided with a housing for accommodating the measurement system and an opening provided at a position of the housing facing the eye to be inspected and through which a measurement light beam passes. The fixation target / mark superposition optical system has a beam splitter and a reflecting member.

(3) The opening of (2) is used as the reference mark.

(4) The ophthalmologic apparatus of (2) is further provided with an observation optical system for observing the eye to be inspected, and the reflecting member is detachably formed in the optical path of the observation optical system optical system.

(5) In an ophthalmologic apparatus having a measurement system for measuring an eye to be inspected, a projection optical system for projecting a fixation target on the eye to be inspected and a first reference mark as a reference for alignment are supplied to the eye to be inspected. First mark forming means and first index forming means for supplying an index to the eye to be inspected by overlapping the first reference mark
An observation optical system for the examiner to observe the eye to be inspected, a second mark forming means for supplying the examiner with a second reference mark serving as a reference for alignment, and the second reference mark overlapping the subject. A second index forming means for supplying an index to the optometry, and the alignment by the examiner and the alignment by the subject are selectively performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The apparatus of this embodiment is a handheld corneal shape measuring apparatus, and FIG. 1 is a perspective view of an optical system when the apparatus of this embodiment is viewed from the side.

Reference numeral 1 is an eye to be inspected, and 2 is a housing of the apparatus. An optical system and an electric system, which will be described later, are housed in the housing 2, and a battery (not shown) is arranged below the housing 2. A measurement window opening 3 is arranged in the housing 2 facing the eye 1 to be inspected, and the alignment of the eye 1 to be inspected is adjusted by observing a fixation target or the like from the opening 3 during measurement.

A is an optical axis of the observation optical system, and a beam splitter 4, an objective lens 5 of a convex lens and a concave mirror 6 are arranged on the optical axis A. The curvature of the concave mirror 6 depends on the opening 3
The opening end of the image is reflected, and its image size is set to be slightly larger than the size of a fixation target described later. Further, the concave mirror 6 is attachable to and detachable from the housing 2 via the holding member 7. In the case of measurement by the examiner, the concave mirror 6 is removed together with the holding member 7, and the examiner sets the objective lens 5 and the beam.
The eye 1 to be inspected is observed through the optical splitter 4. On this occasion,
The examiner can magnify and observe the subject's eye 1 through the objective lens 5, and conversely, the subject's eye 1 can be seen as blurred.

Reference numeral 10 is an aiming mark plate used for measurement by an examiner, for example, an annular mark (not shown) is formed. Reference numeral 11 is a mark plate illumination light source, and 12 is a mirror. The light beam of the aiming mark that has passed through the aiming mark plate 10 when the illumination light source 11 is turned on is reflected by the mirror 12 and the beam splitter 4 toward the examiner's eye, which is a measurer.

Reference numeral 13 is a light source for a fixation target, 14 is a fixation target plate having a spot opening, 15 is a concave lens, and 16 is a dichroic mirror which makes an optical axis of a detection optical system described later and a projection target optical axis coaxial. , 17 are imaging lenses. Light source for fixation target 13
The fixation target plate 14 illuminated by the above is projected onto the fundus of the eye to be examined through the concave lens 15, the dichroic mirror 16, the imaging lens 17 and the beam splitter 4, and the eye 1 to be examined fixes the fixation target plate 14. Can be seen.

Reference numeral 20 denotes an index projection optical system, which has an observation optical axis A.
8 sets are arranged at 45 degree intervals on the same circumference centered on
The projection optical axis forms a predetermined angle with the observation optical axis A. Among the eight sets of index projection optical systems, there are four sets of cornea shape measuring and working distance detecting optical systems 20a to 20d (23c and 23d are not shown) arranged at 90 degree intervals,
The optical systems 20a to 20d include a light source 21, such as an LED, which emits light in the near infrared region, a spot diaphragm 22, and a spot diaphragm 22.
It comprises a collimator lens 23 for keeping the lens at infinity.
The working distance detecting optical systems 23e to 23d (not shown) are composed of a light source 21 and a spot diaphragm 22 and project a finite light flux onto the eye to be examined.

The index detecting optical system includes a beam splitter 4,
It is composed of an imaging lens 17, a telecentric diaphragm 24, and a two-dimensional position detecting element 25. The telecentric diaphragm 24 is arranged at the focal position of the imaging lens 17. The two-dimensional position detecting element 25 is arranged at a position conjugate with the vicinity of the iris where the cornea reflection image is formed with respect to the imaging lens 17, and detects the cornea reflection image by the index projection optical system 20.

Reference numeral 26 is a point light source such as an LED arranged at an interval of 30 degrees on the same circumference centered on the observation optical axis A, and the entire corneal reflection image thereof functions as a earring, and It also serves as the illumination of the anterior segment of the eye.

FIG. 2 is a diagram showing a main part of an electric system block diagram of the apparatus of the embodiment. The signal obtained by the two-dimensional position detection element 25 is subjected to predetermined processing by the signal detection processing circuit 30 and input to the microcomputer 31. The microcomputer 31 performs arithmetic processing based on the input signal, and determines whether the working distance is appropriate or not and obtains the radius of curvature of the cornea.

Reference numeral 32 designates R for selecting the right or left of the eye to be measured.
/ L changeover switch, 33 is a measurement switch, and 34 is a measurer selection switch. The measurer selection switch is a holding member 7.
It can be automatically performed by detecting the presence or absence of wearing. Reference numeral 35 is a display circuit, and 36 is a display.

Next, in the apparatus having the above configuration, the alignment operation when the subject himself / herself performs the measurement will be mainly described.

In the case of measurement by the subject himself, the concave mirror 6
The holding member 7 holding the is attached to the device, and is switched to the subject mode by the measurer selection switch 34. In this state, the subject holds the device with one hand (or holding it with both hands), turns on a power switch (not shown) to turn on each light source (excluding the light source 11), and the R / L switch 32 Determine the left and right of the measurement eye with. Then, the measurement window opening 3 is positioned in front of the selected eye to be inspected.

When the eye 1 to be examined looks into the opening 3, as shown in FIG. 3, the end 3 ′ of the opening 3 and the fixation target light source 13 are illuminated through the concave mirror 6 in the opening 3. The fixation target 14 'is observed.

The state of the observed image of the subject's eye 1 is as follows. In FIG. 4, B is the end diameter of the opening 3, WD is the distance between the eye of the subject and the end of the opening 3, L is the distance between the end of the opening 3 and the concave mirror 6, and R is the concave mirror 6. The radius of curvature. When the objective lens 5 is not provided, the image position of the end portion of the opening 3 formed on the eye side of the subject by the concave mirror 6 is represented by X = R / (R / L-2), and its size is M = It is represented by B · R / (2L−R). B is 20 mm, R is 30 mm, L is 80 m
When m and WD are 45 mm, x is about 18 mm and M is about 4.6 mm.

In this optical system, if the focal length of the objective lens 5 is 250 mm, the end portion 3'is an inverted image having a diameter of about 5.5 mm at a position about 112 mm in front of the eye to be inspected.
The viewing angle is equivalent to 2.8 °.

It is desirable that the fixation target 14 'is placed at a relatively close position in consideration of the refractive error of the eye to be examined.
Placing the fixation target optically at infinity to -1 diopter (1 m in front of the subject's eye) causes no design problem. Further, the visual angle of the fixation target 14 'can be freely set by controlling the size of the spot opening diameter of the fixation target plate 14, for example, 1/1/2 of the visual angle of the opening edge image 3'described above. 4 °

In this way, the alignment adjustment in the vertical and horizontal directions is performed by the opening end 3'observed through the opening 3 and the fixation target 14 '. The subject moves the device up and down, left and right, and adjusts so that the fixation target 14 'is almost at the center of the opening end 3'as shown in FIG. 5, and the optical axis of the observation optical system and the subject's eye are adjusted. Match the visual axes.

It should be noted that the observed opening end 3'and the fixation tag 1
Since the distance from the subject's eye 4'is different, the fixation target 14 '
When the user gazes at, the open end 3'appears to be blurred. However, even if the open end portion 3 ′ looks out of focus, it is easy for the subject to align the positional relationship between the two as described above.

After the alignment adjustment in the vertical and horizontal directions is completed, the working distance is adjusted next. The suitability of the adjustment of the working distance to the subject's eye can be known based on the detection result by the detection optical system of the apparatus.

The working distance is detected by the index projection optical systems 20a to 20d at infinity and the index projection optical system 20e at finite distance.
This is done by comparing the image heights of the corneal reflection images formed by 20h (light sources 21a to 21d and light source 21e).
~ H may be turned on alternately, and the lighting procedure does not matter). This is because when a corneal reflection image is formed by an infinite light source and a finite light source, the image height of the corneal reflection image by the infinite light source does not change even if the working distance changes, but the corneal reflection image by the finite light source. This utilizes the characteristic that the image height of the image changes. The details of this are described in Japanese Patent Application No. 4-224896 (the title of the invention: "alignment detecting device"), so please refer to it.

As for the image height comparison of the corneal reflection images by the light source at infinity and the light source at finite distance, in the case of the light sources at the same position, the suitability of the working distance can be judged if one index image is detected. In the present embodiment, an elliptical shape connecting the corneal reflection images of the index projection optical systems 20a to 20d at infinity by the microcomputer 31 and the index projection optical systems 20e to 20 at finite distance.
Each ellipse shape connecting the corneal reflection images of h is obtained, and the position of each ellipse in the predetermined meridian direction (which may have a constant angle or may be determined as the astigmatic axis direction) is extracted and their heights are compared. Based on this comparison, the microcomputer 31 determines whether the working distance is appropriate, and informs the subject of the determination result by the notifying means. For example, when the device is far from the proper distance with respect to the eye of the subject, the light source 13 for the fixation target is slowly blinked, and blinks quickly as it approaches the eye of the subject. The blinking cycle of the light source 13 is changed. Then, when it is within the permissible range of the proper working distance, it is always turned on. Further, when the appropriate working distance is within the allowable range, a buzzer sound or the like may be used for notification.

When the subject recognizes that the adjustment of the working distance is completed by the notification means of the apparatus, he pushes the measurement switch 33 to start the measurement of the corneal shape. If the microcomputer 31 determines that the image heights match, a trigger signal may be automatically issued to start the measurement.

Regarding the calculation of the corneal shape, the description thereof will be omitted, but the applicant of the present invention has disclosed in Japanese Patent Application Laid-Open No. 61-85920 (“Corneal Shape Measuring Device”, Japanese Patent Publication No. 1-1989).
If three index images are detected as described in No. 6), the corneal shape can be calculated. The measurement result is displayed on the display 36.

The measurement by the subject himself / herself is carried out as described above. However, in the case of the apparatus of this embodiment, when the examiner performs the measurement like a normal ophthalmologic apparatus, the concave mirror 6 is removed together with the holding member 7. Done. The examiner magnifies and observes the eye to be inspected by the objective lens 5 under binocular stereoscopic vision. Marking for aiming 10
And the anterior segment of the eye to be examined, and the ring pattern of the aiming mark.
The observation optical axis and the eye to be examined are adjusted so that the lens becomes concentric with the iris or the limbus.

In adjusting the working distance, the front-back relation of the aiming mark 10 is judged with reference to the Maying image, and the apparatus is moved to a position where the aiming mark 10 is observed at substantially the same distance. Done by Further, the microcomputer 31 determines whether or not the working distance is appropriate based on the detection result of the detection optical system as described above, and notifies the examiner by blinking control of the microphone illumination light source 11. The details of these are described in Japanese Patent Application No. 5-98938 (the name of the invention "ophthalmic apparatus") filed by the present applicant.

An embodiment in which the present invention is applied to a handheld corneal shape measuring apparatus has been described above, but the present invention is not limited to this, and can be applied to various conventional stationary ophthalmic apparatus. Is something that can be done.

The present invention can be modified in various ways,
For example, the concave mirror in the embodiment may be replaced with a convex mirror. Such changes are also included in the present invention to the extent that the technical idea is the same.

[0040]

According to the present invention, with a very simple structure,
The examiner himself can easily and accurately align his own eyes.

Further, by applying to a hand-held type ophthalmologic apparatus which is easy to operate, it is possible to perform the measurement by the subject himself / herself under any favorable environment and mental condition regardless of the place.

Furthermore, the apparatus of the present invention can be easily switched to the measurement by the examiner without using a dedicated apparatus for self-eye measurement.

[Brief description of drawings]

FIG. 1 is a perspective view of an optical system when a device of an embodiment is viewed from the side.

FIG. 2 is a diagram showing a main part of an electrical system block diagram of an apparatus according to an embodiment.

FIG. 3 is a diagram illustrating an end of an opening observed through a concave mirror and a fixation target when an eye to be inspected looks into the opening.

FIG. 4 is a diagram illustrating a state of an observation image by an eye to be inspected.

FIG. 5 is a diagram illustrating an adjustment for matching the optical axis of the observation optical system with the visual axis of the subject's eye.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Eye to be inspected 2 Housing 3 Measurement window opening 6 Concave mirror 14 Fixation target plate 20 Index projection optical system 25 Two-dimensional position detection element 31 Microcomputer

Claims (5)

[Claims] 1. An ophthalmologic apparatus including a measurement system for measuring an eye to be inspected, a projection optical system for projecting a fixation target onto the eye to be inspected,
Mark means for forming a reference mark serving as a reference for alignment, a fixation target / mark superposition optical system for superimposing the reference mark on a fixation target and observing the eye to be inspected, working distance An ophthalmologic apparatus comprising: an index optical system for projecting and detecting an index to determine the suitability of the index, and a determination unit for determining the suitability of the working distance based on the detection result of the index optical system. 2. The ophthalmologic apparatus according to claim 1, further comprising: a housing that houses the measurement system, and an opening that is provided at a position facing the eye to be inspected in the housing and through which a measurement light beam passes. Target
An ophthalmologic apparatus characterized in that the mark superposition optical system has a beam splitter and a reflecting member. 3. The ophthalmologic apparatus according to claim 2, wherein the opening portion is used as the reference mark. 4. The ophthalmic apparatus according to claim 2, further comprising an observation optical system for observing an eye to be inspected, wherein the reflecting member is detachably formed in an optical path of the observation optical system optical system. 5. An ophthalmologic apparatus including a measurement system for measuring an eye to be inspected, a projection optical system for projecting a fixation target onto the eye to be inspected,
First mark forming means for supplying a first reference mark serving as an alignment reference to the eye to be inspected, and first index forming means for supplying an index to the eye to be inspected by overlapping the first reference mark. An observation optical system for the examiner to observe the eye to be inspected, a second mark forming means for supplying the examiner with a second reference mark serving as a reference for alignment, and the second reference mark overlapping the subject. An ophthalmologic apparatus comprising: a second index forming unit that supplies an index to the optometry and selectively performing alignment by an examiner and alignment by an examinee.