JPH05154112A - Ophthalmologic device - Google Patents

Abstract

PURPOSE:To enable the exact and easy execution of alignment and to obtain measured values having high reliability by providing a diaphragm plate provided with plural pieces of optical elements for allowing the transmission of the luminous flux from a cornea reflected image and shutting off the light from a light source for illumination in its peripheral part. CONSTITUTION:Apertures 9a, 9b, 9c, 9d are provided on the diaphragm plate 9. A filter having the characteristic to allow the transmission of the light of the wavelength of the light source 4 for illumination and prohibits the transmission of the light of the wavelength of a light source 5 for index is fitted into the aperture 9a, the center of which is aligned onto an optical axis L. The filters having the characteristics to prohibit the transmission of the light of the wavelength of the light source 4 for illumination and allows the transmission of the light of the wavelength of the light source 5 for index are fitted into the apertures 9b, 9c, 9d. Then, the cornea reflected light beams past the apertures 9b, 9c, 9d are formed to one piece of the bright point on the image pickup surface of a television camera 10 when the eye to be examined is at the prescribed working distance from a nozzle 1. Three pieces of the bright point images which are slightly out-of-focus are formed when the eye to be examined exists in the position far from the prescribed working distance or exists in the excessively nearby position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus, such as a non-contact tonometer, which is required to precisely align a main body of the apparatus and an eye to be examined with a predetermined working distance.

[0002]

2. Description of the Related Art As a working distance adjusting mechanism of a conventional ophthalmologic apparatus, for example, a non-contact tonometer, one disclosed in Japanese Patent Publication No. 56-6772 is known. In this invention, the examiner aligns the eye to be inspected with the nozzle while observing the position of the index image, which is a corneal reflection image, the anterior segment and the sharpness of the index image.

[0003]

However, in the above device, the index image is one circle, and when the working distance is not correct, the same circular blur occurs when the working distance is too far or too close, and it is impossible to distinguish them. Therefore, there is a problem that there is a high risk that the tip of the nozzle accidentally collides with the eye to be inspected. Further, the non-contact tonometer measures by blowing gas onto the cornea of the eye to be inspected, but the eyelashes and hair of the subject may be caught between the nozzle and the cornea at this time, which is a measurement error. Cause. The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to provide an ophthalmologic apparatus capable of performing accurate and easy alignment and obtaining a highly reliable measurement value.

[0004]

In order to achieve the above object, the present invention has the following features. That is, (1) In an ophthalmologic apparatus that requires alignment of the apparatus body and the eye to be inspected with a predetermined working distance, an illumination light source that illuminates the anterior segment and an anterior segment illuminated by the illumination source are provided. An anterior ocular segment observation optical system for observation, an index projection optical system for forming a corneal reflection image by projecting an index light beam of a different wavelength from the illumination light source for alignment on the cornea, and a corneal reflection image A corneal reflection image observation optical system for observing a corneal reflection image, which has a diaphragm plate around which a plurality of optical elements that transmit a light flux and block the light from the illumination light source are provided, and the anterior segment observation It is characterized by comprising an anterior segment image by an optical system and a display means for superimposing and displaying a corneal reflection image by the cornea reflection image observation optical system.

(2) The anterior ocular segment observing optical system and the corneal reflection image observing optical system of (1) are shared, and an aperture is provided in the center of the diaphragm plate for transmitting the light flux from the illumination light source. I am trying.

(3) An optical element for transmitting the light flux from the illumination light source and blocking the indicator light flux is provided in the opening of (2).

(4) The optical elements arranged on the diaphragm plate in (1) are characterized in that they are arranged vertically asymmetrically.

(5) The optical element of (4) is characterized in that it is composed of three optical elements at equal intervals.

(6) The ophthalmologic instrument of (1) is characterized in that it is a non-contact tonometer which blows gas onto the cornea and measures the intraocular pressure based on the amount of deformation.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an optical system arrangement of an embodiment in which the present invention is applied to a non-contact tonometer. Reference numeral 1 is a nozzle that is a gas outlet for corneal deformation, and compressed gas is blown onto the cornea by a piston (not shown), and the amount of deformation is also detected by a light receiving element (not shown) to measure the intraocular pressure (JP-B-54).
-38437). 2 is the eye to be inspected and 3 is its cornea. Reference numeral 4 denotes an illumination light source (for example, a light source having a wavelength of 750 nm is used) for illuminating the anterior segment. The index projection optical system for aligning the eye 2 to be inspected with the instrument is collimating with an index light source 5 (for example, a wavelength of 950 nm is adopted) which is a light source having a wavelength different from that of the illumination light source 4. And a lens 6. The light beam from the index light source 5 is reflected by the half mirror 7, and the optical axis of the index projection optical system and the axis of the nozzle 1 are aligned with each other. The light projected on the eye 2 to be examined forms a virtual image i due to specular reflection of the cornea 3. The optical axis L of the observation optical system is provided so as to coincide with the axis of the nozzle 1. Reference numeral 8 is an objective lens. Reference numeral 9 is a diaphragm plate, and FIG. 2 is a view of the diaphragm plate viewed from the front. Four apertures 9a, 9b, 9c, 9d are provided on the diaphragm plate 9. The center of the opening 9a is aligned with the optical axis L, and light of the wavelength (750 nm) of the illumination light source 4 is transmitted, but the index light source 5 is used.
A filter having a characteristic of not transmitting light of the wavelength (950 nm) is fitted. Further, the openings 9b, 9c, 9d are provided at equal distances from the optical axis L at equal intervals, so that the light of the wavelength of the illumination light source 4 is not transmitted and the light of the wavelength of the index light source 5 is transmitted. A filter having characteristics is fitted to each. Reference numeral 10 is a TV camera, and 11 is a TV monitor for displaying the output from the TV camera 10.

Next, the positioning operation by the apparatus having the above-mentioned structure will be described. The light from the illumination light sources 4 arranged above and below illuminates the anterior segment of the subject's eye. The light from the anterior segment of the illuminated eye 2 passes through the nozzle 1 and the
After passing through the Fumilla-7 and the aperture 9a of the diaphragm plate 9, the anterior ocular segment image is formed on the television camera 10 by the objective lens 8. The light of the wavelength of the illumination light source 4 can be transmitted only through the aperture 9a by the filter on the diaphragm plate 9, and the spread of the light flux is limited. Therefore, the object depth in the anterior ocular segment image observation becomes deeper than that of the virtual image i. .. Therefore, the examiner is the TV monitor 1
While performing the alignment operation on 1, the eyelashes to the iris can be observed relatively clearly.

On the other hand, the light emitted from the index light source 5 is collimated.
After being converted into a parallel light flux by the holding lens 6, it is reflected by the half mirror 7 and projected onto the cornea 3 from the front. The light projected on the cornea 3 forms a virtual image i due to specular reflection of the cornea 3. The reflected light of the cornea 3 that appears as if it were emitted from the virtual image i passes through the openings 9b, 9c, 9d, and then is reflected by the objective lens 8 on the television camera 10 to form the virtual image i.
Forming an image of. When the eye to be inspected is at a predetermined working distance with respect to the nozzle 1, the corneal reflected light that has passed through the openings 9b, 9c, 9d is formed at one bright spot on the image pickup surface of the television camera 10 and is displayed on the television monitor 11. It is observed as in FIG. 3A (the anterior segment image is omitted). When the eye to be inspected is located at a position farther than a predetermined working distance, as shown in (b), and when it is too close, as shown in (c), three blurry bright spot images are formed. The examiner observes the images of the anterior segment image and the virtual image i on the television monitor 11 to perform the working distance and axis alignment between the eye to be inspected and the nozzle 1. Since the positional relationship between the eye to be inspected and the instrument and the distance can be easily discriminated from the relationship between the anterior eye image and the bright spot, the examiner operates the joystick based on this information, and the examiner operates a well-known sliding mechanism. The device is moved relative to the eye to be inspected, and alignment is performed.

The above embodiment can be variously modified,
For example, the index and the anterior segment of the eye may be separately captured and image-synthesized so as to be displayed on the same monitor. Further, a half mirror may be installed obliquely between the diaphragm and the television camera to display an alignment mark such as a ring slit on the television camera. I explained only the non-contact tonometer,
It is obvious that the present invention is not limited to this and can be used in various ophthalmologic devices such as an eye refractometer.

[0014]

According to the present invention, alignment can be performed accurately and easily, a highly reliable measurement value can be obtained, and an accident such as the nozzle tip colliding with the eye to be examined can be avoided.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical system arrangement of an apparatus according to an embodiment.

FIG. 2 is a front view of a diaphragm plate.

3A and 3B are views showing an image of a diaphragm, where FIG. 3A shows a proper case, FIG. 3B shows a case that is too far, and FIG. 3C shows a case that is too close.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Eye 3 Eye cornea 4 Light source for illumination 5 Light source for index 9 Aperture plate 10 Television camera 11 Television monitor

Claims (6)

[Claims] 1. An ophthalmologic apparatus that requires aligning a device body and an eye to be inspected with a predetermined working distance, and an illumination light source for illuminating an anterior segment of the eye, and an anterior segment illuminated by the illumination light source. An anterior segment observation optical system for observing, and an index projection optical system for forming a corneal reflection image by projecting an index light flux of a different wavelength from the illumination light source for alignment on the cornea,
A corneal reflection image observation optical system for observing a corneal reflection image, having a diaphragm plate provided with a plurality of optical elements for transmitting a light flux from the corneal reflection image and blocking light from the illumination light source, An ophthalmologic apparatus comprising: a display unit that superimposes and displays an anterior segment image by the anterior segment observation optical system and a corneal reflection image by the corneal reflection image observation optical system. 2. The anterior ocular segment observation optical system and the corneal reflection image observation optical system according to claim 1 are shared, and an opening for transmitting a light flux from the illumination light source is provided in the center of the diaphragm plate. Ophthalmic device to do. 3. An ophthalmologic apparatus characterized in that the opening according to claim 2 is provided with an optical element that transmits a light beam from an illumination light source and blocks an index light beam. 4. The ophthalmologic apparatus according to claim 1, wherein the optical elements arranged on the diaphragm plate are arranged vertically asymmetrically. 5. An ophthalmologic apparatus, wherein the optical element according to claim 4 is composed of three pieces at equal intervals. 6. The ophthalmologic apparatus according to claim 1, which is a non-contact tonometer that blows gas onto the cornea and measures the intraocular pressure based on the amount of deformation.