JPS5839526B2 - Shikinou Kensa Sochi - Google Patents

Description

[Detailed description of the invention] The present invention relates to an apparatus for testing visual function.

Conventionally, this type of inspection equipment has been commonly used to apply a critical fusion frequency method, or the so-called CFF method. By increasing the length, the subject responds when the optotype, which was initially seen continuously without feeling flickering, flickers and becomes visible, and the visual function is determined from the flickering time interval or frequency at that time. It is something.

However, it is difficult to obtain a stable value at the detection point of such a response without considerable training, and there is also a drawback that there is no way to accurately confirm whether or not the target change is visible or not during the response.

Instead of the conventional one-dimensional detection of boundaries by distinguishing between mere flickering of an optotype, the present invention constructs an optotype using a superimposed image of a positive image and a negative image of the same size and shape,
The images are made to blink alternately at intervals that gradually and continuously change, and in the middle of this process, when the figure of the optotype that was initially unrecognizable comes to be recognized, the image that was initially recognized when young The system detects the blinking time interval or frequency when the image becomes unrecognizable, and by performing multidimensional detection such as shape recognition, even inexperienced subjects can perform test measurements relatively easily and accurately. It was made possible to do so.

To explain the embodiment with reference to FIG. 1, 1 is a light source that is turned on by a power source 2, 31, 3□ are two condenser lenses provided between the light source 1, and 41
, 42 is a mirror, 50, 5□ is a field lens, 61
, 6□ are the same shapes with the same size and have a positive and negative relationship with each other,
Two charts for forming optotypes are arranged at the same relative position, and these charts are, for example, a graphic representation of a Landolt ring in a positive and negative state as shown in FIGS. 2A and 2B.

7, 8□, 82 are mirrors, 9 is a semi-transparent mirror, 10 is an imaging lens, 11 is an optotype display surface, and 12 is a rotating sector as shown in FIG. 3, which is provided in front of both charts. 13 is a chopper rotation motor, 14 is a motor drive power source, 15 is a motor transmission, 16 is a motor rotation speed detector, and 17 is a detector 1.
6, a photo pickup or other suitable rotational speed indicator.

In the above device, the light emitted from the light source 1 is divided into two optical paths by condenser lenses 31, 32, mirrors 4□, 4□, field lenses 51, 52, etc.
62, the light from both charts passes through the mirror 7 or mirrors 81 and 8□, and is combined by the semi-transparent mirror 9, and the images of both charts are displayed on the optotype display surface 11 in a superimposed manner by the imaging lens 9. I will do it.

At this time, if there is a difference in the brightness of the images from the two optical paths due to the reflectance of the mirror or other factors, it is preferable to insert a suitable light amount adjustment device 18 in one or both of the optical paths to adjust the brightness.

When the subject looks at this optotype display surface 11 with the eyes 19 at an appropriate distance, the display surface is uniformly illuminated because the images from the two optical paths are in a positive and negative matching state, and the figure on the chart is cannot be recognized at all.

At this time, if the chopper 12 is operated by the motor 13 to alternately pass the light from both charts, if the number of changes in the pass is sufficiently high, it will not be possible to recognize what the target image is. By operating the transmission 15, the chopper 1
If the speed of step 2 is gradually lowered, the shape of the image will be recognized after a certain point.

Therefore, the visual function can be tested and measured by having the subject respond to that effect and reading the blinking interval or frequency at that time from the display 17.

In addition, when responding, if the figure that the subject recognized is a Landolt ring, for example, the subject's recognition can be confirmed by having the subject answer the dog/monkey direction of the figure, or if it is a letter or other figure, what it is.

In addition, when testing the same subject repeatedly, if the chart remains as it was at the beginning, it is possible to predict the shape that will appear, which may lead to measurement errors. By rotating the chart to change the broken position, and for other shapes, replacing the chart with another shape will help prevent errors caused by prediction.

The embodiment shown in FIG. 4 does not use two optotype forming charts, but instead has a light transmitting part 6A and a light reflecting part 6 as shown in FIG.
A positive image and a negative image are formed on the optotype using only one chart 6 whose figures are represented by B and B.

In this example, the above-mentioned chart 6 is installed obliquely on the optical path that passes from the light source 1 through the condenser lens 3, and the field lens 50 and the mirror 201°2 are on the reflected optical path for this chart.
0□, 203 are provided in sequence, and a field lens 52 and a mirror 21 are placed on the optical path passing through the chart 6.

21□ and 213 are sequentially provided, and the light from both optical paths is combined by a semi-transparent mirror 9, and the positive and negative images of the chart 6 appear on the optotype display surface 11 in a superimposed manner through the imaging lens 10. A chopper 12 is provided in the middle of both optical paths to straddle them and alternately cut the optical paths.
It can be used in the same way as the example in the figure.

The embodiment shown in FIG. 6 is a development of the example shown in FIG.
Two relatively large mirrors 20A and 20B are used in common for two optical paths for positive images and negative images, thereby reducing the number of total reflection mirrors, facilitating adjustment, and making the entire system compact. It is.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the main structure of one embodiment of the device of the present invention, Fig. 2 is a plan view of a chart used therein, and Fig.
The figure is a plan view of the plate constituting the chopper, Fig. 4 is a plan view of another embodiment, Fig. 5 is a plan view of a chart used therein, and Fig. 6 is a plan view of the embodiment of man 1. . 1: Light source, 2: Power supply, 3, 31, 3□: Condenser lens, 40, 4□: Mirror, 50, 5□: Field lens, 6, 6. ．． 62: Chart, 7: Mirror 8□,
8□: Mirror, 9: Semi-transparent mirror, 10: Imaging lens,
11: optotype display surface, 12: chopper 13: motor,
14: Power supply, 15: Transmission, 16: Rotation speed detector, 17
: Rotation speed display, 18: Light amount adjustment device, 19: Subject's eyes, 201, 202° 203: Mirror, 20A, 20
B: Mirror 211°21□, 213: Mirror.

Claims (1)

[Claims] 1. A positive image and a negative image of the same size and the same figure are superimposed to form an optotype, and the images are made to flicker alternately and the blinking interval is gradually and continuously changed during the process. , a device that tests visual function by finding the boundary point between when the figure in the original image cannot be recognized and when it can be recognized, and detecting the blinking interval or frequency of the image at that time. 2 Line up two charts of the same size and shape with different positive and negative relationships, combine the light emitted from them through a semi-transparent mirror, and display the images of both charts on the optotype display surface through an imaging lens. The images are formed in a superimposed manner, and the light from both charts is passed through alternately using a chopper, etc., and the passing interval is gradually and continuously changed. A device that finds the boundary point between when a figure cannot be recognized and when it can be recognized, and detects the time interval or frequency of light transmission at that time. 3 Transmitted light and reflected light from one chart representing a figure with a light transmitting part and a reflecting part are combined by a semi-transparent mirror, and a positive image and a negative image are created by transmission and reflection of the chart through an imaging lens. The transmitted light and the reflected light are alternately passed through using a chopper or the like, and the passing interval is gradually and continuously changed to produce an image on the optotype display surface. Visual function is tested by finding the boundary point between when the figure on the original chart cannot be recognized in the optotype and when it can be recognized, and detecting the time interval or frequency of light transmission at that time. device to do.