JPH0397432A - Fixed view device of perimeter - Google Patents

Abstract

PURPOSE:To provide perfect coincidence of the positions of two fixed targets and allowing the center measuring fixed target to be discerned correctly even by a half-blind person to be inspected by selectively lighting up the periphery measuring fixed target consisting of dot-shaped bright parts and the center measuring fixed target consisting of a plurality of bar-shaped bright parts. CONSTITUTION:A fixed target projection part is equipped with a mask for a periphery measuring fixed target 300 to be projected to the central position O and two types of masks for four linear center measuring fixed targets 302 located in four radial directions with the fixed view position O as center, and the two fixed targets shall be capable of being projected alternately onto the upper part of a hemispherical dome by replacement of these masks. Accordingly, there is no dislocation between the fixed target position due to the periphery measuring fixed target and the fixed target position due to the center measuring fixed target, and high precision measurement of the view field can be made by fixing the collimation line of the eye inspected so as to be directed always in a constant direction.

Description

Detailed Description of the Invention (Industrial Field of Application) In a perimetry that sequentially forms a plurality of visual targets on a spherical screen and determines the visual field of the eye to be examined based on the visual recognition status of these targets by the eye to be examined, the visual field is measured. The present invention relates to a fixation device for fixing the collimation line direction of an eye to be examined at approximately the center of a spherical screen.

(Prior Art) A conventional fixation device is provided with a fixation monitoring window at the center of a spherical screen for monitoring the collimation direction of the eye to be examined from behind the spherical screen. The fixation target for peripheral measurement consists of a dot-like bright area placed within this fixation monitoring window, and the fixation target for center measurement consists of four dot-like bright areas formed at a position away from the fixation monitoring window. It was formed as a central location.

(Problems to be Solved by the Invention) In conventional fixation devices, there is a positional deviation between the fixation target for peripheral measurement and the fixation target for central measurement, that is, the center position of the four bright areas. There was a problem in that the direction of the line of sight was different between peripheral visual field measurement and central visual field measurement, making it impossible to perform highly accurate visual field measurement.

In addition, the fixation target for center measurement, which consists of four dot-shaped bright areas, is observed as two dots when a hemianopic subject aims at it, making it impossible to estimate the center of the fixation target and to avoid directing the line of sight. There was also the problem of not being able to correctly orient the device to the fixation point for central measurement.

The present invention has been made in view of the above-mentioned problems of the conventional visual field fixation device, and is designed to completely match the position of the fixation target for peripheral measurement and the position of the fixation target for center measurement, and The purpose of the fixation target for center measurement is to provide a fixation device that can be correctly viewed even by a hemianopic subject.

(Structure of the Invention) The present invention provides a perimeter measurement device that measures the visual field using an optotype formed on a spherical screen. , consisting of a central measurement fixation target consisting of a plurality of rod-shaped bright parts formed on a plurality of rays centered on the peripheral measurement fixation target except for the vicinity of the center, and selectively illuminated. This is a visual fixation device for a perimeter.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 2, the automatic visual field measurement device includes a housing 10, a panel 14 provided with a circular hole 12 for inserting the subject's face and attached to the front side of the housing 10, a recognition switch 16, and It has a face fixing part 22 consisting of a forehead rest 18 and a chin rest 20 attached to the housing 10 to fix the face in a predetermined position, and an operation display device 26 attached to the side wall 24 of the housing 10. The lower side wall near the front of the panel 14 has a handle 28 for moving the face fixing part 22 vertically and horizontally. Inside the housing 10, a large number of LEDs 29 are provided throughout the inner surface for displaying visual targets.
A hemispherical dome 30 is built in.

The operation display device 26 includes a TV monitor 32 and a light pen 3.
4. Printer 36 located below the TV monitor 32;
It consists of a control switch 38 placed above the TV monitor 32 and a fixation monitoring telescope 40. The TV monitor 32 displays the type of optotype and the optotype distribution presented on the inner surface of the hemispherical dome 30, as well as a plurality of operation commands to be described later, and the device is operated by selecting an operation command using the light bezel 34 and the control switch 38. do.

Printer 36 prints the measurement results. The fixation monitoring telescope 40 monitors from the front whether or not the subject's eye is aiming at the fixation target position located at the center of the spherical surface of the hemispherical dome 30, and is approximately referred to as the fixation target position 0. The anterior segment of the subject's eye during measurement is monitored through the aperture at the same location.

The fixation target projection unit 50 is composed of a fixation target projection optical system 52 arranged on the upper part of the hemispherical dome and a fixed mirror 54 arranged slightly above the center of the hemispherical dome. The images of 52 masks are projected onto a hemispherical dome via a fixed mirror to form a fixation target.

This fixation target projection unit 50, as shown in FIG. 1(a),
A mask of the fixation target 300 for peripheral measurement projected at the center position ○, and four linear center measurement points located in four radial directions around the fixation position O, as shown in FIG. 1 (6). It has two types of masks for the fixation target 302, and by exchanging these masks, the fixation target for peripheral measurement or the fixation target for center measurement can be projected alternately onto the upper part of the hemispherical dome.

Next, the structure of this embodiment will be explained based on FIG. 3. I
The /O interface 100 receives the light pen 34 operated by the measurer, the output signals from the control switch 38, and the recognition signal from the recognition step 16 which inputs whether or not the person to be measured recognizes the visual target. , converts the input signal into a signal suitable for processing by the internal device, and converts the measurement result into a signal suitable for printing on the printer 36. Although the description here assumes that the person to be measured operates the recognition switch 16 himself, the measurer may receive recognition from the person and manually operate the recognition switch 16 using a light pen.

The CPU 102 performs main control of the apparatus, and performs various timing controls in addition to the contents described later using a flowchart.

The LED matrix ink face 103 is
According to the optotype presentation conditions read by 02, the corresponding LED
29 is an ink face for lighting up under predetermined conditions, and a matrix is formed by at least two transistor arrays.

The presentation condition storage unit 104 stores optotype presentation conditions that determine how the LEDs 29 of the dome 30 are lit, that is, combinations of lighting brightness (intensity), position, lighting time, etc., as a plurality of visual field measurement programs. I remember.

The green inner circle test program, which is one of the visual field measurement programs stored in the presentation condition storage unit 104, displays the fixation target 300, as shown in FIG.
302, consists of a first step of presenting the optotype 200 indicated by a black circle, and a second step of presenting the optotype 202 indicated by a white circle.

The optotypes 200 in the first step are distributed over the entire measurement field of view, with circles 204 and 2 indicating collimation angles of 10° and 20°.
The distribution density of the so-called Bjelm region sandwiched by 06 and the region extending outward from the symmetrical position of the blind spot with respect to the fixation point (hereinafter referred to as "Nazal step region") is higher than the distribution density of the visual target 200 in other areas. It has become. This structure of the optotype distribution density is because visual field defects due to the inner circle tend to appear in the Bjerlum region and the Nazal step region, and it is generally difficult to detect or diagnose glaucoma by measuring the visual field only in this region.

The second step optotype 202 is obtained by removing the first step optotype 200 from the general visual field measurement optotype distribution,
By presenting the optotypes in both the first step and the second step, normal visual field measurement can be performed for the entire visual field.

Note that, in order to eliminate measurement inaccuracies due to predictions of the subject's presentation, the optotypes are presented randomly at each step using a random number signal from a random number generator (not shown). Further, although the optotype distribution for the left eye test is shown in FIG. 4, the optotype distribution for the right eye test is the one shown in 4rXJ, which is horizontally reversed.

GDC (Graphic Display Coitorola) 1
10 is an LED array signal, a selected measurement program signal is a signal indicating the position of the lit LED, and the response signal is inputted to form an image signal for displaying information of these signals on the TV monitor 32. and add this to video memory 1
Output to 12.

Timing control circuit 114 forms a suitable timing signal from the clock signal output from clock oscillator 116 and outputs a timing signal from GDC 110, CPU 102 and video memo! , 1112.

The P/S converter 118 performs parallel-to-serial conversion on the parallel digital signal from the video memory 112 to form a video signal and outputs it to the TV monitor 32.

Next, the operation of the CPU I O 2 will be explained based on the flowchart shown in FIG. First, a predetermined program is selected from the measurement programs displayed on the TV monitor 32 using the light pen 34, and in the following, it is assumed that the Midoriuchin program has been selected. Subsequently, the optotype presentation conditions of the l-th step are read from the presentation condition storage unit 104, and
The LEDs 29 arranged on the inner surface of the hemispherical dome 30 are sequentially turned on via the LED matrix ink face 103 to present the optotype.

On the other hand, the response of the subject to the presentation of the optotype is manually inputted and stored through the recognition step 16.

In addition, the measurer issues the command to output the measurement results to the TV monitor while viewing the optotype presentation and the response status of the person being measured.
Enter by 4. That is, at any time during the presentation of the optotype, the measurer can input an output command to stop the presentation of the optotype when he or she determines that the optotype is sufficient for diagnosing glaucoma.

If this output command signal is not input, it is then determined whether or not the first step of displaying the optotype has been completed. 1st
If the visual target presentation of the step is completed, then the second
It is determined whether or not the optotype presentation of the step has been completed, and if it has been completed, the measurement results are output, and it is determined whether all measurement procedures have been completed, and all measurements by the program are completed. do.

When determining whether or not the output command signal has been input, if the output command signal is input, the output form is determined based on the measurement results of the previous measurements, and it is difficult to determine whether all measurements have been performed. Proceed to step.

If it is determined that the first step has not been completed in determining whether or not the optotype presentation in the first step has been completed, the process proceeds to the step of reading out the optotype presentation conditions in the first step and continues. The first step of visual target presentation is then performed.

If it is determined that the second step has not been completed in determining whether or not the visual target presentation of the second step has been completed, the second step visual target presentation condition is read from the presentation condition storage unit 104, and As in step 1, the LEDs 29 are sequentially turned on to present the visual target. The subject's response to the presentation of the visual target in the second step proceeds to the stage of memorizing the subject's response, which is input via the recognition switch 16.

Furthermore, if it is determined that all measurements have not been completed, the process proceeds to the step of determining whether or not the output command signal is input.

In the above embodiment, the optotype is formed by an LED, but the present invention can also be effectively implemented with a perimeter that forms the optotype using a projection method. In this case, it is necessary to arrange the movable mirror for projecting the measurement target and the fixed mirror for projecting the fixation target so that they do not interfere with each other.

(Effects of the Invention) According to the present invention, the fixation target is a peripheral measurement fixation target consisting of a dotted bright area formed approximately at the center of a spherical screen, and a plurality of peripheral measurement fixation targets centered on the peripheral measurement fixation target. A fixation target for center measurement is formed from a plurality of rod-shaped bright parts formed on the radiation line except for the vicinity of the center. Therefore, in the present invention, there is no positional deviation between the fixation target position by the peripheral measurement fixation target and the fixation target position by the central measurement fixation target, and the line of sight of the subject's eye is always directed in a constant direction. It has the advantage of being able to perform highly accurate visual field measurements while being fixed in place.

Furthermore, the present invention provides a fixation target for central measurement even if only two bar-shaped bright areas are visible by a hemianopic subject
The subject should take the intersection of the extension lines of these two rod-shaped bright areas or
Another advantage is that it can be easily recognized that the intermediate position between the two bar-shaped bright parts is the fixation target position.

[Brief explanation of drawings]

Fig. 1 (a) is a structural and explanatory diagram of the present invention, Fig. 2 is a perspective view of an automatic visual field measuring device according to an embodiment of the present invention, and Fig. 3 is a block diagram of an electric circuit according to the embodiment. FIG. 4 is an explanatory diagram of the optotype distribution in the optotype presentation step, and FIG. 5 is a flowchart showing the operation of the CPU. DESCRIPTION OF SYMBOLS 10... Housing, 16... Recognition switch, 26... Operation display device, 29... LED, 30... Hemisphere dome, 32... TV monitor, 36...・・Printer, 38・#- Control switch, 100・・・Engineering/0 interface, 102・・・・
CPU, 103...LED matrix, 104...Presentation condition storage unit, 108...Response storage unit, 200, 202...Optotype, 300...Fixation target for peripheral measurement , 302... optotype for center measurement. (a) 302 (b) 302 Figure 2

Claims (3)

[Claims] (1) In a perimeter that measures the visual field using an optotype formed on a spherical screen, a fixation target for peripheral measurement consisting of a point-like bright area formed approximately at the center of the spherical screen, and the fixation target for peripheral measurement. A perimeter meter comprising a fixation target for center measurement consisting of a plurality of rod-shaped bright parts formed on a plurality of rays centered on the target except for the vicinity of the center, and which is selectively illuminated. fixation device. (2) The fixation target for peripheral measurement and the fixation target for center measurement are projected images projected through a reflective member fixed near the forehead of the subject. Perimeter fixation measurement. (3) The fixation target for a perimeter according to claim 1, wherein the visual target formed on the spherical screen is formed by an LED.