JPH06285025A - Ophthalmologic device - Google Patents

Abstract

PURPOSE:To provide the ophthalmologic device which is simple in constitution and has an adequate sighting mechanism by adopting the constitution to judge whether alignment is adequate or inadequate by comparing the cornea of the eye to be examined with the size of a mark for sighting. CONSTITUTION:An inspector observes the anterior eye part of the eye 1 to be examined via an observation lens 5 and a beam splitter 8 with its both eyes. The inspector can observe the mark for sighting in superposition on the image of the anterior eye part of the eye 1 to be examined via the beam splitter 8. The vertical and lateral alignment is executed by moving the device in such a manner that the mark for sighting is concentrical with the corneal ring part. Further, whether the working distance is adequate or inadequate is roughly judged by comparting the cornea of the eye 1 with the mark for collimation. The working distance is roughly adjusted by moving the device in such a manner that the diameter in the horizontal direction of the cornea and the mark for collimation are observed at nearly the same size. The device detects whether the working distance is adequate or inadequate by using an optical system for measurement in parallel therewith. The measurement is started if it is at an adequate position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmic apparatus, and more particularly to an alignment mechanism for an eye to be inspected and an ophthalmic apparatus, and more particularly to a mechanism suitable for adjusting a working distance of a handheld type apparatus.

[0002]

2. Description of the Related Art Many ophthalmic apparatuses are of a stationary type, and as an alignment mechanism of this type, a traditional method is known in which an examiner directly observes an eye to be examined through an eyepiece tube. In this type of device, when the eye to be inspected is placed at a predetermined distance, an index is projected on the eye to be inspected so that the images match one, and the suitability of the working distance is determined. The advantage of this method is that it can be made relatively inexpensive, and because it is a pure optical system, it enables precise image observation within the range allowed by the resolving power of the eye.

In recent years, a system in which the eye to be inspected is imaged with infrared light and displayed as a visible image on a TV monitor has become widespread. In this apparatus, the optical axis is adjusted by placing an eye image to be inspected, an alignment mark superimposed on the eye image to be inspected, and a first Purkinje image formed by corneal reflected light in a predetermined positional relationship. , The working distance is adjusted by adjusting the focus to the formation position of the first Purkinje image. The advantages of this method are that it is not affected by the diopter of the examiner, and that it is possible to aim in a comfortable posture at a distance from the eye to be examined.

[0004]

However, since the subject and the examiner approach each other in the former device of the traditional method, the subject is uncomfortable and the examiner is forced to take an unreasonable posture. There is a point. Further, the latter type of device has a problem that it becomes an expensive and large-sized device because a television camera and a television monitor are required. There is also a problem that the image quality is inferior to the former method. When the iris is used as a reference for alignment, it may be difficult to distinguish it from the pupil depending on the color of the iris. In view of the above-mentioned drawbacks of the conventional apparatus, it is an object of the present invention to provide an ophthalmologic apparatus having a simple structure and an appropriate aiming mechanism.

[0005]

In order to solve the above problems, the present invention is characterized by having the following configuration. (1) In an ophthalmologic apparatus that requires aligning the device at a predetermined position with respect to the eye to be inspected, an observation system for observing the eye to be inspected, and an anterior segment of the eye to be inspected when the working distance is appropriate. Mark forming means arranged at a substantially conjugate position to form an aiming mark having a size comparable to the size of the cornea of the eye to be examined, and the mark forming means provided on the optical axis of the observation system. A light splitting member for guiding the light flux to the examiner's eye is provided, and suitability of alignment is judged by comparing the sizes of the cornea of the eye to be inspected and the aiming mark.

(2) The aiming mark of (1) is characterized in that it is an annular mark having substantially the same size as the limbus of the cornea of the eye to be examined.

(3) The aiming mark of (1) is characterized in that it is an annular point index having substantially the same size as the corneal limbus of the cornea of the eye to be examined.

(4) The ophthalmologic apparatus of (2) or (3) is an eye refractive power measuring apparatus, and the aiming mark formed by the mark forming means has a measurable minimum pupil diameter. Is a ring or a plurality of points on the same ring.

(5) An ophthalmologic apparatus characterized in that a convex lens for magnifying and observing the anterior segment is arranged in the optical path of the observation system of (1).

(6) The ophthalmologic apparatus of (1) has a second detection optical system for determining whether the working distance is appropriate, and a trigger signal for issuing a trigger signal based on the detection result of the second detection optical system. And generating means.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of the optical system of the apparatus of the first embodiment. Reference numeral 1 is an eye to be inspected, 2 is an examiner's eye, and 3 is a housing of the apparatus. In order for the examiner's eye 2 to observe the subject's eye 1, a through-hole 4 is provided in the housing 3, and the examiner's eye 2 has an observation lens 5
The eye 1 to be inspected is viewed through the eye. The observation lens 5 is for magnifying and observing the eye 1 to be inspected, the distance between the observation lens 5 and the eye to be inspected is 75 mm, the distance from the observation lens 5 to the eye 2 to be inspected is 200 mm, and the focal length of the observation lens 5 is Is 250 mm, a 1.28 times magnified image can be obtained.

An illumination light source 6 illuminates the aiming mark plate 7. An aiming mark is formed on the aiming mark plate 7 as shown in FIG. Numeral 7a is a dot-shaped mark arranged on an annulus having a diameter of about 11 mm which is almost the same size as the corneal limbus, which is slightly smaller than the horizontal diameter of 11.5 mm of a Japanese cornea ( The corneal diameter has a small individual difference compared to the pupil diameter). 7b may be a line in which the astigmatic axis of the measurement system indicates the 0 degree direction. Further, a line extending in the 90 ° direction may be provided. The light that has passed through the aiming mark plate 7 is reflected by the beam splitter 8 arranged in the observation optical path and heads for the eye 2 to be inspected. As the optical characteristics of the light splitting member, various transmission / reflection characteristics can be selected in consideration of the wavelength of the aiming mark, the wavelength of the measuring light, the arrangement position thereof and the like.

Reference numeral 10 is an index projection optical system for measuring the shape of the cornea, which is arranged at intervals of 90 degrees on the same circumference centered on the optical axis. Index projection optical systems 10a to 10d (10c,
10d is not shown) is an LED 1 that emits light in the near infrared region.
1, a spot diaphragm 12 and a collimator lens 13. The collimator lens of the index projection optical system 10a escapes out of the optical path in order to set a finite index when the working distance is detected.

Reference numeral 14 denotes an image forming lens, which is one of the image forming lenses.
A telecentric diaphragm 15 is arranged at the focal position of 4. Reference numeral 16 is a beam splitter that divides light into two, and one-dimensional position detecting elements 17a and 17b are arranged in each of the divided optical paths so that the detection directions intersect with each other. Telecentric diaphragm 15 and one-dimensional position detecting element 1
Cylindrical lenses 18a and 18b are arranged between 7a and 17b such that the axes thereof coincide with the detection direction. It is designed so that the optical path lengths from the beam splitter 8 to the aiming mark plate 7 and the corneal limbus of the eye 1 to be examined are equal when the eye to be examined is at a predetermined design distance from the imaging lens 14. It is arranged so that the working distance between the measurement optical system and the eye to be inspected is appropriate when the size of the corneal limbus of the eye to be inspected and the size of the aiming mark are substantially the same. If the corneal limbus, which is the boundary between the cornea and the sclera, is used as a reference, it can be clearly seen even in an apparatus that directly observes the eye to be examined.

The adjustment of the working distance of the apparatus having the above structure will be described. The examiner uses both eyes to observe the observation lens 5 and the beam splitter 8.
The anterior segment of the subject's eye 1 is observed through the. The inspector is
The aiming mark can be superposed on the anterior ocular segment image of the subject's eye 1 through the optical splitter 8. Vertical and horizontal alignment is performed by moving the device so that the aiming mark and the limbus are concentric.

Furthermore, the suitability of the working distance is roughly determined by comparing the sizes of the cornea of the eye 1 to be inspected and the aiming mark. When the anterior segment of the eye 1 to be inspected and the aiming mark are overlapped with each other, the corneal limbus becomes smaller than the aiming mark as shown in FIG. When the device is too close, the cornea is visible larger than the aiming mark, as shown in b. A rough adjustment of the working distance is performed by moving the device so that the horizontal diameter of the cornea and the diameter of the aiming mark are observed to be approximately the same size.

In parallel with such a rough adjustment of the working distance, the device detects the suitability of the working distance by using a measuring optical system. When detecting the working distance, the collimator lens of the index projection optical system 10a is made to escape from the optical path and the image heights of the corneal reflection images formed by the index projection optical systems 10a and 10b are compared. 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 characteristic is that the image height changes. The details of this are described in Japanese Patent Application No. 4-224896 (the title of the invention: "alignment detecting device") by the present applicant, so please refer to it. Based on the detection results by the one-dimensional position detecting elements 17a and 17b, the image height of the corneal reflection image of the finite light source is compared with the image height of the corneal reflection image of the infinity light source, and a micro computer (not shown). ) Determines whether the working distance is appropriate. The position where the image heights match is the proper position. When it is determined that the image heights match with each other according to a predetermined standard, the microcomputer
Emits a trigger signal to start measuring the corneal shape.

For measuring the shape of the cornea, Japanese Patent Application No. 59-2075
No. 39 (Title of Invention: Corneal Shape Measuring Device, Japanese Patent Publication 1-1
If three index images are detected as described in No. 9896), the corneal shape can be calculated. Therefore, the collimator lens of the index projection optical system 10a can be measured with the collimator lens left out of the optical path, but in this embodiment, in order to obtain highly accurate data, the collimator lens is obtained by obtaining the alignment completion signal. The motor is moved into the optical path and the corneal shape is measured based on the coordinate positions of four points.

In the above description, the mechanism for moving the device with respect to the eye to be examined is not mentioned, but this is because the handheld type device is kept in mind. However, the application of the present invention is not limited to this type of device, and can be applied to a known stationary joystick type device. Further, in an apparatus such as an eye refractometer in which the minimum pupil diameter required for measurement is determined, the aiming mark is arranged at a ring or a position corresponding to the minimum pupil diameter as shown in FIG. It is good to set points.

[0020]

According to the present invention, a working distance adjusting mechanism having an extremely simple structure can be realized. Moreover, since the distance between the examiner and the device in the observation direction can be freely set, the examiner can perform measurement in a comfortable posture.

[Brief description of drawings]

FIG. 1 is a side view of an optical system of an apparatus.

FIG. 2 is a view showing an aiming mark plate.

FIG. 3 is a diagram illustrating a view image capturing of an anterior segment including a sighting mark image.

FIG. 4 is a view showing another aspect of the aiming mark plate.

[Explanation of symbols]

 1 eye to be inspected 2 eye to be inspected 3 corneal shape measuring device 4 through-hole 5 objective lens 6 illumination light source 7 aiming mark plate 8 beam splitter

Claims (6)

[Claims] 1. An ophthalmologic apparatus that requires aligning the device to a predetermined position with respect to the eye to be inspected, an observation system for observing the eye to be inspected, and an anterior eye of the eye to be inspected when the working distance is appropriate. Mark forming means for forming an aiming mark having a size comparable to the size of the cornea of the eye to be examined, which is arranged at a position substantially conjugate with the eye, and the mark provided on the optical axis of the observation system.
And a light splitting member for guiding the light flux of the forming means to the examiner's eye,
An ophthalmologic apparatus characterized by judging the suitability of alignment by comparing the sizes of the cornea of the eye to be inspected and the aiming mark. 2. The ophthalmologic apparatus according to claim 1, wherein the aiming mark is an annular mark having substantially the same size as the limbus of the cornea of the eye to be examined. 3. The ophthalmologic apparatus according to claim 1, wherein the aiming mark is a ring-shaped point index having substantially the same size as the limbus of the cornea of the eye to be examined. 4. The ophthalmologic apparatus according to claim 2 or 3 is an eye refractive power measuring apparatus, and the aiming mark formed by the mark forming means is a ring showing a measurable minimum pupil diameter. Alternatively, the ophthalmologic apparatus is characterized by a plurality of points on the same ring. 5. An ophthalmologic apparatus, wherein a convex lens for magnifying and observing the anterior segment is arranged in the optical path of the observation system according to claim 1. 6. The ophthalmologic apparatus according to claim 1, further comprising a second detection optical system that determines whether the working distance is appropriate, and a trigger signal generation that generates a trigger signal based on the detection result of the second detection optical system. An ophthalmologic apparatus comprising: