SU150978A1 - Instrument for the examination of visual acuity - Google Patents

Description

Instruments for investigating visual acuity, comprising a housing with a handle, test objects deposited on a frosted glass and a lighting electric bulb, are known.

In the proposed device, in contrast to the known cube-shaped illumination lamp, is located in the center of the housing, on the top and side faces of which windows for inserting cassettes with test objects are cut. Such a device device provides uniform illumination of all test objects, as well as portability of the device by the rational use of surfaces to place objects. In order to present the individual test objects or a group of them in the device, there are installed dampers overlapping any of the test objects located on the side faces of the case, and for accurate setting the distance from the device to the lamp tube examined on the core .

FIG. 1 shows a general view of the proposed device; FIG. 2 - the bottom wall of the device with an electric lamp and a handle.

The device case has the shape of a cube, on the top and side walls / -Which windows 2 are cut through; Cassettes with glass matte plates, on which test objects 3 are applied to examine visual acuity, are inserted into the top and side walls of this cube. As objects for adults, open Landolt rings are used, and for children, drawings; house, plane, etc. Inside the case, in the center of the cube, an electric bulb 4 is placed, fixed in cartridge 5 on the bottom wall of the cube. A handle 6 is fastened on the outer side of the lower wall, inside of which an electric cord 7 with a length of 5 m passes. On the shield 7 there are applied distance marks 150978

ki, allowing the distance from the device to the patient to be established at the time of the study. An electric lamp 4 placed in the center of the cube provides almost uniform uniform illumination of objects located in any of the sections of the four side walls, as well as the upper wall.

In the upper wall of the instrument case, one object (the largest) is inserted for a visual acuity of 0.1; Interchangeable objects can be placed in the windows of the side walls for visual acuity from 0.2 to 1.0. All windows of the side walls are closed with movable metal shields 8, which provides an isolated presentation of objects to the subject. One set of objects is replaced with another one when the bottom wall is separated from the body with a handle 6 and a light bulb 4 by simply replacing the cassettes.

The light bulb 4 is turned on and off by a push-button switch 9 mounted on the bottom wall of the device. The device allows to measure visual acuity at a distance of up to 5 m. Table 10 is strengthened for calculating corrections when measuring from distances less than 5 liters on the outside of the bottom wall.

When using the device, the doctor holds his hand 6 on a certain distance from the patient, presented him with test objects. The same object can be shown in various positions by turning the device so that the same side is facing the patient.

Subject invention

1. An instrument for examining visual acuity, comprising a housing with a handle, test objects deposited on a frosted glass and a lighting electric bulb, characterized in that, in order to ensure uniform illumination of all test objects and ensure portability of the device by rational use of surfaces for The object is located in the center of the cube-shaped body, on the top and side edges of which the windows for inserting cassettes with test objects are cut.

2. Device on 1P. 1, characterized in that, in order to present the individual test objects or their groups to the test person, a screen-shutter is installed that overlaps any of the test objects located on the side faces of the housing.

3. Device on PP. 1 and 2, characterized in that, in order to accurately set the distance from the device to the one under investigation, distance marks are placed on the shield of the lamp holder.

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