SU1377017A1 - Ophthalmologic refractometer - Google Patents

Abstract

The invention is intended for ophthalmology. The purpose of the invention is to improve the accuracy of measuring the refraction of the eye. The device includes two light sources 1 and 2, an optical illumination channel containing a condenser 3, a movable diaphragm 4 attached to the measuring bar 5, mounted at the focus of the lens 6, an optical recording channel containing a beam splitter 7 installed in the optical illumination channel, the focusing system from lenses 8 and 9, the photodetector 10, the comparator 11 and the actuator 12. The reflectometer is also equipped with a beam splitter 13 and additional optical illumination and recording channels. By changing the orientation of the slits relative to the eye to be examined by the same amount, it becomes possible to measure the refraction of the eye in another section, which is important for detecting the degree of astigmatism. 1 il.

Description

Eye

(L

with

V4

The invention relates to medical instrumentation and is used in ophthalmology to assign glasses to patients.

The aim of the invention is to improve the accuracy of measuring the refraction of the eye.

The drawing shows the scheme of the ophthalmic refractometer.

The device includes two light sources 1 and 2, an optical illumination channel containing a condenser 3, a movable aperture 4 attached to a measuring scale 5 installed in the focus of the lens 6, a lens 6, an optical recording channel containing a beam splitter 7 installed in the optical illumination channel a focusing system of two lenses 8 and 9, a photodetector 10, a comparator 11 and an actuator 12. In addition, the ophthalmologic refractometer is additionally equipped with a beam splitter 13, additional optical illumination channels and a register The light sources 1 and 2 are installed on the optical axes of the optical illumination channels. Single-area photodetectors electrically connected to the inputs of the co.parator 11 are used as photodetectors 10. The additional illumination channel may contain a mirror 14. Splitter 13, mirror 14, movable aperture 4 and the lenses 8 are located on the same platform and have the possibility of simultaneous displacement along the optical axes of the recording channels through the actuator 12.

The operation of the device consists in extracting an electrical signal at the executor 1H mechanism 12 for joint displacement of the beam splitter 13, mirror 14, lens 8 and diaphragm 4 along the optical axis of the focusing object b to a position where the image quality of the latter on the retina is the same. This electric signal is formed by a comparator 11, depending on the difference in the light fluxes fed to the photodetectors 10 located in the optical recording channels.

The operation of each of the optical recording channels consists in the fact that if, when illuminating aperture 4 with a light source 1 or 2, its image is not optically coupled to the retina of the eye being studied, then the luminous flux reflected from the retina and falling on the photodetector 10 is less than than in the case of conjugation. Since the optical channels operate alternately, with a switching frequency that the eye cannot register, and there is a difference in position between the aperture 4 times from the focus of its lens 6, the change in the optical power of the eye, aimed at observing that of the aperture, corresponds to the relaxation of the eyes that

causes a change in the light fluxes on the photodetectors 10, as a result of which the actuator 12 shifts the diaphragms 4 to the position corresponding to the complete relaxation of the eye. Wherein

the preferential observation of one of the diaphragms is absent, the image of one of them is located behind the retina, and the second is in front of the retina. If the plane conjugate to the retina of the examined eye is not located between the diaphragms, then in this case there is an inequality of light fluxes on the photodetectors 10, the difference signal from which determines the direction of the corresponding offset of the diaphragms 4. The position of the diaphragms 4 along The optical axis of the focusing lens 6 is a function of the refraction of the eye under investigation, the value of which is determined by the measuring scale 5.

If the diaphragms 4 are made in the form of slits and are oriented in one direction relative to the focusing lens 6, then the device allows to determine the refraction of the eye only in the cross section of the eye, perpendicular to the direction of the slits.

By changing the orientation of the slits relative to the eye to be examined by the same value, it becomes possible to measure the refraction of the eye in another cross section, which is important for determining the degree of igigmatism.

Claims (1)

Invention Formula Ophthalmic Refractometer, including two light sources, an optical illumination channel comprising a condenser; movable diaphragm fastened to the measuring pin, mounted in the lens focus, lens, optical recording channel containing a beam splitter installed in the optical illumination channel, focusing and photo-receiving system, nickname, comparator and actuator associated with the diaphragm, characterized by that, in order to improve the accuracy of measuring the refraction of the eye, it additionally equipped with a beam splitter, additional optical illumination and recording cannons, the light sources being installed on the optical axes of the optical illumination channels; photo detectors in the optical recording channels are used single-site photodetectors electrically connected to the inputs of the comparator.