JP3107237B2 - Non-contact tonometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact tonometer.

[0002]

2. Description of the Related Art A non-contact tonometer for measuring the intraocular pressure by spraying a fluid onto a cornea of an eye to be examined to deform the cornea, and detecting the deformed state of the cornea has been well known. In this conventional non-contact tonometer, the alignment of the device with the eye to be examined is important, but the alignment adjustment is performed with the examiner's face fixed to the face support device and the examiner's face reflected on the TV monitor or the like. This has been done by moving the apparatus body by operating the operation lever while viewing the image.

[0003]

However, the non-contact tonometer has a working distance between the cornea to be examined and the device of about 11 mm, which is extremely short as compared with other ophthalmic instruments. Nevertheless, since high-precision alignment is required, the examiner must be watching the front image of the eye on the TV monitor while performing the alignment operation at the time of measurement.
Therefore, the examiner cannot know the distance between the apparatus and the subject's eye during the alignment, and is concerned about contact and collision between the apparatus and the subject's eye. In addition, they may actually come into contact with each other.

The present invention has been devised in view of the above-mentioned drawbacks, and allows the examiner to know the distance between the apparatus and the subject's eye while the examiner performs the alignment operation so that the examiner can make contact with the eye in advance. It is an object of the present invention to provide a non-contact tonometer capable of avoiding the problem.

[0005]

To achieve the above object, the present invention is characterized by the following. That is, (1)
Alignment adjustment means for adjusting the alignment with respect to the eye to be inspected, and display means for displaying a front image of the eye to be inspected to the examiner, and deforming the cornea by spraying a fluid onto the cornea of the eye to be inspected to detect the deformed state of the cornea In a non-contact tonometer for measuring intraocular pressure, a side observation optical system for observing the eye to be examined from the side, and a side image display means for displaying a side image of the eye to be examined by the side observation optical system to the examiner, It is characterized by having.

(2) The side image display means of (1) is characterized in that a front image of the eye to be examined is simultaneously displayed on the same screen as the display means for displaying to the examiner.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an optical system layout diagram showing the non-contact tonometer of the present embodiment. 1, reference numeral 1 denotes an optical axis of a front observation optical system;
Denotes an optical axis of a side observation optical system, 3 denotes an eye to be inspected, and 4 denotes a cornea of the eye to be inspected. Reference numeral 5 denotes a nozzle for injecting a gas for deforming the cornea,
The front observation optical system is installed along the optical axis 1. Reference numeral 6 denotes an alignment light source, and reference numeral 7 denotes a half mirror provided on the optical axis 1. Reference numeral 8 denotes an objective lens , and 9 denotes a lens having a focal position on the TV camera 10. 11 is a mirror, 12 is an objective lens, and 13 and 14 are mirrors, respectively. Reference numeral 15 denotes a TV camera for observing the side surface of the eye 3 to be inspected. 1
Reference numeral 6 denotes a composite circuit for synthesizing two images obtained by the TV cameras 10 and 15 in a predetermined arrangement. Reference numeral 17 denotes a television monitor for displaying the video. The light projecting system, the light receiving system, and the control system for measuring the intraocular pressure are not shown.

Next, the operation of this embodiment will be described. The light emitted from the alignment light source 6 is reflected by the half mirror 7 and is irradiated on the cornea 4 via the lens 8 along the optical axis 1 of the front image observation optical system. The light beam reflected by the cornea 4 passes through the lens 8, the half mirror 7, and the lens 9, is condensed into a bright spot image, and is incident on the TV camera 10. The TV camera 10 observes the subject's eye 3 from the front via the lens 8, the half mirror 7, and the lens 9. The side surface of the eye 3 is observed by the TV camera 15 through the mirror 11 arranged on the side of the eye 3, the objective lens 12, the mirror 13, and the mirror 14.

[0009] The two images obtained by the TV cameras 10 and 15 are converted into video signals, synthesized by the composite circuit 16 into a predetermined arrangement, and output side by side on the TV monitor 17 at the same time. The examiner looks at the front image 18 of the subject's eye displayed on the TV monitor 17 and operates an alignment operation lever (not shown) to adjust the bright spot image 19 on the front image 18 of the subject's eye to a predetermined position on the screen. I do. During this time, the distance between the apparatus and the subject's eye 3 can be confirmed by the side face image 20 of the subject's eye that is simultaneously displayed, and the lever is operated so that the subject's eye 3 does not come into contact with the apparatus.

In order to display a side image of the subject's eye in the measurement of either the left or right eye, the above-described two side observation optical systems may be installed. In this case, for example, as shown in FIG. 2 and FIG. 3, if a part supporting the inner mirror 11 of the lens barrel is designed to be of a drawer type,
It is possible to prevent the mirror 11 of the side observation optical system on the unused side from interfering with measurement such as contact with the face of the subject. Further, the two images of the front and side surfaces of the subject's eye do not necessarily need to be projected on the same screen, and may be separate images, and these changes are naturally included in the present invention.

[0011]

As described above, according to the present invention,
Since the examiner can know the distance between the apparatus and the subject's eye while performing the alignment operation, it is possible to avoid contact between the apparatus and the subject's eye in advance.

[Brief description of the drawings]

FIG. 1 is an arrangement diagram of an optical system of a non-contact tonometer according to an embodiment.

FIG. 2 is a cross-sectional view showing a part of a side observation optical system.

FIG. 3 is a cross-sectional view showing a part of a side-viewing optical system in a state where a mirror is stored.

[Explanation of symbols]

 10,15 TV camera 11,13,14 Mirror 12 Objective lens 16 Composite circuit 17 TV monitor

Claims (2)

(57) [Claims] The present invention has an alignment adjusting means for adjusting alignment with respect to an eye to be inspected, and a display means for displaying a front image of the eye to be inspected to an examiner. In a non-contact tonometer that detects a deformation state and measures intraocular pressure, a side observation optical system for observing an eye to be examined from the side, and a side surface for displaying a side image of the eye to be examined by the side observation optical system to an examiner A non-contact tonometer, comprising: image display means. 2. A non-contact tonometer according to claim 1, wherein said side image display means simultaneously displays a front image of the eye to be examined on the same screen as a display means for displaying to an examiner.