JPH02136124A - Perimeter - Google Patents

Abstract

PURPOSE:To enhance visual field measuring accuracy by preventing the generation error even when a glance moves at the time of the measurement of a visual field by detecting a glance direction and correcting a target projecting position on the basis of the detected glance direction. CONSTITUTION:A target projection system is constituted so that the stimulation light from a stimulation light generator 2 is projected on a screen 1 through a lens 3 and a mirror 4 and an examinee S is allowed to answer whether he sees the stimulation light to detect a visual field. Then, a glance direction is detected and, as a correction means of a target projecting position due to said glance direction, the light from an infrared ray source 8 is reflected by a half mirror 5 to irradiate an eye E to be examined and the anterior part image of the eye to be examined is projected on a monitor television camera 7 by a lens 6. The glance direction is analyzed from the anterior part image by a signal processing part 9 and the analyzed result is fed back to the stimulation light generator to correct the showing position of the stimulation light. By this method, the target projecting position is corrected even when slight glance shift is generated to make it possible to prevent the generation of an error.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention presents a visual target using stimulating light to a subject, and allows the subject to respond as to whether or not the visual target is visible.
This invention relates to a perimeter that is fixed at a certain distance.

[Prior Art] Generally, in this type of automatic perimeter, the visual field Δ111
It is necessary to monitor the line of sight because errors occur when the line of sight of the subject's eye moves at regular intervals.

Conventionally, the following two methods are mainly used to monitor this line of sight. One method is for the examiner to monitor whether or not the eye to be examined is in a predetermined position by projecting the anterior eye segment image on a monitor, but with this method, even if the position of the eye to be examined is known, the line of sight The disadvantage is that it is not fully understood. Another method is to occasionally shine stimulating light in the direction of the papilla of the subject's eye and see if the subject responds to it. In this case, since there is no foreknowledge of the nipple, if there is a reaction from the subject, it will be known that the patient's line of sight has shifted, but with this method, it can only be detected occasionally, and the nipple is not dotted, but rather spread out, even if slightly. , there is a drawback that a sufficient detection viscosity cannot be obtained (11). Therefore, in this conventional method, the visual field 'A1
1 Constant value is prone to errors due to line of sight deviation < , +11
There is a problem that the 11 constant accuracy is not very good.

[Object of the invention] The object of the present invention is to improve the problems of the conventional example as described above,
To provide a highly accurate perimeter that corrects the visual field shift and prevents errors even if there is a slight shift in the visual field during visual field measurement.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned objects is as follows.
an optotype projection system for projecting a regular optotype, a detection means for detecting the line of sight direction of the eye to be examined, and a means for correcting the optotype projection position of the optotype projection system based on the line of sight direction detected by the detection means. This is a perimeter that is characterized by being equipped with.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows an embodiment of the perimeter according to the present invention, in which a hemispherical screen l is arranged in front of the subject S, and the stimulating light emitted from the stimulating light generating device 2 is directed onto the screen l. 3. The image is projected through a mirror 4. In addition, on the M side of the eye E to be examined, a half mirror 5 and a lens 6 are provided.
, surveillance cameras 7 are arranged in sequence, and an infrared light source 8 is arranged in the direction of incidence of the half mirror 5. The output of the monitoring camera 7 is connected to a signal processing section 9, and the output of this signal processing section 9 is connected to the stimulating light generating device 2.

The optotype projection system projects stimulus light emitted from a stimulus light generator 2 onto a screen 1 via a lens 3 and a mirror 4, and causes the subject S to respond as to whether or not this stimulus light has illuminated. to detect the field of view.

On the other hand, as a means for detecting the direction of the line of sight and correcting the target projection position based on the direction of the line of sight, in the embodiment, the light emitted from the infrared light source 8 is reflected by the half mirror 5 to illuminate the eye E to be examined. The anterior eye image of E is projected onto the monitoring television camera 7 through the lens 6 as shown in FIG. Correct the presentation position of the stimulus light by feeding back to and always test eye E
optotype at a given position relative to ? as shown.

This line-of-sight direction analysis is performed by determining, for example, the relative position of the corner 11X2 reflected image (2) of the infrared light source 8 and the pupil P in FIG. 2 as follows. That is, the scanning lines a, b, and c in FIG. 2 become the signals A, B, and C in FIG. 3, and the pupil edge is obtained from A, B, and C in FIG. 3, and the corneal image is obtained from B2, so The relative position of these intersections can be calculated from ((f+).

This relative position changes when the line of sight of the eye E to be examined is tilted, but since this fluctuation varies from person to person, calibration is required at the start of the Δ11 constant. Furthermore, the Burkinier image can be used as another eye monitoring device, that is, the relative position of the corneal reflection image I and the reflection image of the posterior surface of the crystalline lens may be used. In this case, it is necessary to apply illumination from an oblique direction and separate the two images on the pupil in advance.

[Effects of the Invention] As explained above, the perimeter according to the present invention detects the direction of the line of sight and corrects the optotype projection position based on the detected direction of the line of sight. Also, there is no error, and the accuracy of determining the field of view Δ111 can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the perimeter according to the present invention, in which Fig. 1 is a configuration diagram, Fig. 2 is an explanatory diagram of an anterior segment image projected on a surveillance television camera, and Fig. 3 is a video thereof. It is a waveform diagram of a signal. 1 is a screen, 2 is a stimulating light generator, 3 is a lens, 4 is a mirror, 5 is a half mirror 16 is a lens, 7 is a monitoring television camera, 8 is an infrared light source, and 9 is a signal processing section. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. An optotype projection system that projects an optotype for visual field measurement, a detection means that detects the line of sight direction of the eye to be examined, and a correction of the optotype projection position of the optotype projection system based on the line of sight direction detected by the detection means. A perimeter meter characterized by comprising means for: