JP3154533B2 - Ophthalmic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmic apparatus which requires precise alignment of a main body of the apparatus and an eye to be examined with a predetermined working distance, for example, an ophthalmic apparatus such as a non-contact tonometer.

[0002]

2. Description of the Related Art As a working distance adjusting mechanism of a conventional ophthalmic apparatus, for example, a non-contact tonometer, the mechanism disclosed in Japanese Patent Publication No. 56-6772 is known. In the present invention, the examiner performs the alignment between the eye and the nozzle while <br/> observing the sharpness of the position and index images of the index image is a corneal reflection image.

[0003]

However, in the above-described apparatus, the index image is a single circle. When the working distance is not correct, when the distance is too far and when the distance is too close, a similar circular blur occurs, and it is not possible to distinguish. Therefore, there is a problem that there is a high risk that the tip of the nozzle collides with the eye to be examined by mistake. In addition, a non-contact tonometer performs measurement by blowing gas onto the cornea of the subject's eye.At that time, eyelashes and hair of the subject may be caught between the nozzle and the cornea, which is a measurement error. Cause. The present invention has been devised in view of the above-described drawbacks, and has as its technical object to provide an ophthalmologic apparatus capable of performing accurate and easy alignment and obtaining highly reliable measurement values.

[0004]

To achieve the above object, the present invention has the following features. That is, (1) an illumination light source for illuminating an anterior segment, and the illumination light source
An anterior segment imaging optical system for imaging the anterior segment illuminated by
Has, device main body and the ophthalmic apparatus for aligning the eye to be examined and the predetermined working distance, an index projecting optical that the indicator light flux of wavelength different from that of the illumination light to form a projected image of corneal reflection towards the cornea System, and is shared with the anterior ocular segment imaging optical system.
In the light path, the light from the corneal reflection image is shielded at the center.
A first filter that transmits the illumination light;
A plurality of light beams that transmit the light flux from the film reflection image and block the illumination light
Are provided asymmetrically with respect to the optical axis, respectively.
The other parts have aperture plates that block both light beams,
Capture corneal reflection image using corneal reflection light transmitted through filter
And a corneal reflection image imaging optical system that passes through the first filter.
Anterior ocular segment image and corneal reflection image captured using different illumination light
Display means for superimposing and displaying a corneal reflection image by an imaging optical system
Are provided .

[0005]

[0006]

[0007]

[0008]

[0009]

[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 denotes a nozzle which is an ejection port of a gas for deforming the cornea. The compressed gas is blown onto the cornea by a piston (not shown), and the amount of the deformation is detected by a light-receiving element (not shown) to measure the intraocular pressure.
-38437). 2 is the eye to be examined and 3 is the cornea. Reference numeral 4 denotes an illumination light source for illuminating the anterior ocular segment (for example, a light source having a wavelength of 750 nm is employed). An index projection optical system for positioning the eye 2 and the instrument is collimated with an index light source 5 (for example, a wavelength of 950 nm), 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 ha - is reflected by the half mirror -7, the optical axis with the axis of the nozzle 1 of the index projecting optical system is canceller matched. The light projected on the eye 2 forms a virtual image i by 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. 8 is an objective lens. 9 is an aperture plate,
FIG. 2 is a view of the same as viewed from the front. 4 on the diaphragm plate 9
There are provided openings 9a, 9b, 9c, 9d.
The aperture 9a has a center aligned with the optical axis L, and is fitted with a filter having a characteristic of transmitting light of the wavelength (750 nm) of the illumination light source 4 but not transmitting light of the wavelength of the index light source 5 (950 nm). Have been. The openings 9b, 9c, and 9d are provided at regular intervals at a position separated from the optical axis L by a predetermined distance.
Each of the filters has a characteristic of transmitting light having a wavelength of?. Reference numeral 10 denotes a television camera, and reference numeral 11 denotes a television monitor that displays an output from the television camera 10.

Next, a description will be given of a positioning operation performed by the apparatus having the above configuration. Light from the illumination light sources 4 arranged above and below illuminates the anterior segment of the subject's eye. The illuminated light from the anterior segment of the eye 2 passes through the nozzle 1 and
After passing through the aperture 7a of the diaphragm 7 and the aperture plate 9, an anterior eye 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 aperture plate 9, and the spread of the light beam is limited. Therefore, the object depth in observing the anterior ocular segment image is deeper than that of the virtual image i. . Therefore, the examiner should use the TV monitor 1
While performing the alignment operation on 1, it is possible to observe relatively clearly from the eyelashes to the iris.

On the other hand, the light emitted from the index light source 5 is collimated.
After being converted into a parallel light beam by the focusing lens 6, the light 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 by specular reflection of the cornea 3. The reflected light of the cornea 3, which appears as if it were emitted from the virtual image i, passes through the openings 9b, 9c, 9d and is then displayed on the television camera 10 by the objective lens 8 on the television camera 10.
An image is formed. When the subject's eye is at a predetermined working distance with respect to the nozzle 1, the corneal reflected light passing through the openings 9 b, 9 c, and 9 d is formed as one bright spot on the imaging surface of the television camera 10, and The image is observed as shown in FIG. 3A (the anterior segment image is omitted). When the eye to be inspected is located at a position farther than the predetermined working distance, three blur-like bright spot images are formed as shown in (b), and when the eye is too close, as shown in (c). The examiner observes the image of the anterior eye part and the virtual image i on the television monitor 11 to adjust the working distance and the axis between the eye to be inspected and the nozzle 1. Since the positional relationship between the subject's eye and the instrument and the distance can be easily determined from the relationship between the anterior segment image and the bright spot, the examiner operates the joystick based on this information and operates the well-known sliding mechanism. Moves the apparatus relative to the subject's eye to perform alignment.

The above embodiment is capable of various modifications.
For example, the index and the anterior segment may be separately imaged and projected on the same monitor by image synthesis. Further, a half mirror may be obliquely provided between the aperture and the television camera to project an alignment mark such as a ring slit on the television camera. I explained only the non-contact tonometer,
It is apparent that the present invention is not limited to this, and can be used for various ophthalmic devices such as an ocular 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 that the tip of the nozzle collides with the eye to be inspected can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic view 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 show a state of an image of an aperture, where FIG. 3A shows a case where it is appropriate, FIG. 3B shows a case where it is too far, and FIG. 3C shows a case where it is too close.

[Explanation of symbols]

 Reference Signs List 1 nozzle 2 eye to be examined 3 cornea 4 light source for illumination 5 light source for index 9 aperture plate 10 TV camera 11 TV monitor

Claims (1)

(57) [Claims] 1. An illumination light source for illuminating an anterior segment, and the illumination
Eye imaging light for imaging the anterior eye illuminated by the light source
In an ophthalmologic apparatus having a medical system and positioning the apparatus main body and the subject's eye at a predetermined working distance, an index light flux having a wavelength different from that of the illumination light is projected toward the cornea to form a corneal reflection image. Both the index projection optical system and the anterior ocular segment imaging optical system
In the optical path used, the luminous flux from the corneal reflection image is
A first filter that blocks light and transmits the illumination light;
Transmits the luminous flux from the corneal reflection image and blocks the illumination light.
A plurality of second filters asymmetrically with respect to the optical axis.
The other part has an aperture plate that blocks both light beams,
Corneal reflection image using corneal reflection light transmitted through the second filter
Corneal reflection image pickup optical system for picking up the image, and the first filter
Anterior ocular segment imaged using illumination light passed through and the cornea
A table that superimposes the corneal reflection image by the reflection image imaging optical system
An ophthalmologic apparatus characterized by comprising: indicating means .