JPS6321493B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention simultaneously projects a fixed mark onto a projection screen placed in the line of sight of the patient's eyes and forms a corresponding mark on the respective position of the visual field map. The present invention relates to an improved device for fixing a patient's eye and measuring the visual field in an ophthalmological examination using the same method as described above. The position of each of the marks is automatically recorded on the field map.

In most conventional visual field meters, the operator checks the patient's eye gaze direction through a telescope, but this method has the disadvantage that the checking is haphazard. A visual check is difficult to perform during this routine visual field test.

In other known methods, for example as disclosed in East German Patent Specification No. 140 840, the position of the patient's eyes is monitored by means of the infrared spectrum and any deviation from its fixed orientation is detected by an optical signal and/or an audible signal. A photoelectric measuring device is employed which is displayed by a signal and printed on the inspection evaluation data unit.

These visual and electronic management systems
Patients are forced to look in one direction during the entire 10-minute test. This is extremely cumbersome given that many of the people who have to undergo such tests are very old and can reduce the quality of the test results or increase the time required for such tests for physiological reasons. Let me do it. A further disadvantage of electronic monitoring devices is their relatively high cost.

In most recent perimeter perimeter configurations, the fixed point is displaced over a range of angles in order to obtain continuous measurements of the patient's eye field in combination with discrete test marks. It is becoming more and more common. The fixed marks therein are projected onto the central pole of the hemispherical perimeter screen and are adjustable to any point within this range, which range corresponds to the distance between the discrete test marks.

Therefore, it is an object of the present invention to eliminate the above-mentioned disadvantages.

Another object of the invention is to provide a method for automatically maintaining fixation of the patient's eyes during visual field testing, which requires less time for the test, improves the quality of the test, and is less burdensome for the patient during the test. We are here to provide you with a method.

The above and still another object of the invention is to project a point to be fixed onto a screen provided in the direction of the patient's line of sight and simultaneously project a mark corresponding to the point to be fixed onto a visual field map. This is achieved by automatically maintaining fixation of the patient's eyes during a type of ophthalmological visual field test.

As the marks on the field map are recorded, the position of the illuminated test mark in the field of the patient's eye will also be accumulated.

According to the invention, the projection beam for projecting a fixed point and a corresponding mark is arranged so that the fixed point is circular on a preselected path around a preselected zero point in the central part of the perimeter screen. controlled to move. The movement of the fixed point is continuous and carried out over a small range of a few degrees in angle and at a slow readout rate. Therefore, the patient's eyes can easily follow the fixation point. If the fixation point were to move quickly, it would eliminate the abnormal muscle effort that occurs when the eye looks at a fixed direction for long periods of time during the test. According to the method of the present invention, measurement failures and repeated measurements are avoided, and physiological stress on the patient during the examination is also reduced.

Conveniently, the path of motion of the fixed point is a straight line, a flat ellipse or a circle. The fixed point is imaged by a projector or other suitable optical system onto the concave surface of the hemispherical perimeter screen.

A further advantage of the invention is that the central part of the perimeter can be made translucent and its fixation point can be created by back projection of a projector arranged opposite the convex surface of the perimeter. It is. The actual position of the fixed point in relation to the test mark is transferred to the field map by optical means or some other suitable means, such as, for example, an electronic detector.
Preferably, this optical transfer takes place with a double projector arranged opposite the convex surface of the perimeter.
This double projector creates a fixed point on its perimeter screen and at the same time creates a corresponding mark on the field map. Both the fixed point and the mark are moved in combination by tilting or displacing the dual projector or by displacing the aperture in each of the two projector beams.

The method according to the invention can be applied independently of the manner in which test marks are produced. They may therefore be produced by projection and also realized by light exit surfaces of optical cables or by light-emitting diodes.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, advantages, and invention itself of the present invention will become more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, which schematically illustrate preferred embodiments thereof.

In FIG. 1, a projector 1 creates a fixed point 2 illuminated in rear projection on a light-transparent central portion 4 of a hemispherical perimeter screen 3. In FIG. A light emitting device 5 illuminates test marks onto the concave surface of the screen 3, one of which is also represented and designated by the reference numeral 6.

The positioning unit 7 serves to change the position of the fixing point 2 within its central part 4. For this purpose, the projector 1 is seated, for example, in a universal joint 16 and via a cardanian universal suspension means for the projector, for example a hinge member 17, which may actually be in the same position as the positioning unit 7. It is connected to the positioning unit 7. It is therefore also possible to combine the hinge point 17 and the positioning unit 7 to form a suspended positioning unit 7. It is also possible to design this element 17 as an elastic rod or as a very rigid spring attached to the projector 1. In this case, a very simple periodic rotational movement of the projector 1 can be realized. The unit 9 is used to ascertain the actual position of the test mark with respect to the fixed point 2 and to record this position in the field map 11; therefore, the unit 9 is connected to the projector 1 and the field map 11. has been done. The key 10 allows the patient to record both marks in the visual field map 11 via respective means not shown. The patient's eyes 12 are in respective positions in front of the concave surface of the perimeter 3. During the examination process, the patient's eyes1
2 follows the fixed point 2 moving at a low scanning speed on a preselected elliptical path within the central part 2 according to well-known physiological reflex actions.

A light emitting device 5 illuminates a test mark 6 on the hemispherical perimeter 3. The position of the test mark system in the patient's field of vision depends on the relative position of the test mark 6 to the actual position of the fixation point 2. Positioning with respect to fixation points and test marks is performed by the patient using key 1.
0 to indicate that he has recognized that test mark 11, mechanical and optical systems ensure that the actual position of the test mark relative to its fixation point is recorded in the field map 11. related by means (not shown in detail).

FIG. 2 shows the hemispherical perimeter 3 of FIG. 1 as viewed from the patient's side. The fixation point 2 is relative to the zero point 18 in the direction indicated by the arrow 13 along an elliptical path 14 in the central part 4 with a border 15 (not visible to the patient) indicated by a dotted line. and move. A test mark 6 selected from a plurality of possible test marks on the perimeter 3 is illuminated and recognized in its position relative to the fixed point 2.

The ellipse 14 in the perimeter 3 has a center at the zero point 18, a maximum extension in the horizontal direction and a minimum extension in the vertical direction.
Its maximum extension is at an angle of 4° and its minimum extension is
They are at an angle of 0.4° and the common center of both angles is placed on the patient's eye. Fixed point 2 moves at a speed of 2 degrees per second.

[Brief explanation of the drawing]

1 is a schematic diagram of an arrangement for carrying out the method according to the invention, and FIG. 2 is a schematic diagram of a perimetry as seen from the patient's point of view. DESCRIPTION OF SYMBOLS 1...Projector, 2...Fixed point, 3...Perimeter screen, 4...Light-transmitting central portion, 5...Light emitting device, 7...Positioning unit, 9...Detection unit, 10... Key, 11...Visual field map, 12...
...Patient's eye, 16... Universal joint, 17... Hinge member.

Claims (1)

[Scope of Claims] 1. A device for fixing a patient's eye and measuring the visual field in an ophthalmological examination, comprising: means for projecting a fixed point onto a certain plane; means for causing a relative periodic movement to be visually followed by the patient; means for producing a test mark on said surface at a distance from said fixation point; means for recording the points of the test mark as viewed while fixing the eye at the fixed point; and means for allowing the patient to manipulate the means for recording the points of the test mark. Device. 2 The projected fixed point is continuously moved along an elliptical path, the center of which coincides with the zero point, and the maximum horizontal displacement angle is 4°. Device according to claim 1, wherein the speed is 2°/sec.