RU2133103C1 - Method for examining and restoring binocular vision - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves carrying out phase mode division of vision fields by showing objects separately to the right and left eye. Vision field division is carried out by applying liquid crystal spectacles. The objects are shown with frequency being enough for excluding flickering effect. Distance to an object is increased by applying spherical prismatic spectacles. EFFECT: enhanced effectiveness in reducing vision fields division influence; excluded test field flickering; practically infinite vision field.

Description

 The proposed method relates to the field of ophthalmology and is intended for the study and restoration of binocular vision.

 Known methods for studying and restoring binocular vision (orthoptic and diploptic) and devices for their implementation are based on the separation of the visual fields of both eyes, i.e. haploscopy. Various principles of haploscopy are used - mechanical separation of fields (synoptophores, synoptoscopes (8)), color (anaglyphs (4)), polaroid (polaroids of various designs (2)), raster (raster glasses, Bagolini glasses (5)). Separation of the visual fields of both eyes is necessary for recording the right and left monocular images, but the uncoupling effect should be minimal.

 Methods for restoring binocular vision (methods for restoring the reflex of bifixation, a method of uncoupling accommodation and convergence) provide a reduction in the haploscopic effect by successively changing the prismatic or spherical effect of the glasses. The method of color filters is based on reducing the haploscopic effect by reducing the density of the filter.

 A similar approach provided an increase in the percentage of binocular vision recovery from 33.5% (on synotypic devices with mechanical separation) to 44-45% (diploptic methods).

 The development of diagnostic methods and functional treatment in the closest to natural conditions is ongoing to this day.

 The principle of phase separation of fields is known, which is the most physiological, since this is consistent with the theory of transmission of nerve impulses alternately in phase mode (3, 6, 7).

 The principle of phase presentation of test objects in a rough form is presented in synoptophore with a frequency of 2-8 flickers per second. The disadvantage of this method is the combination of the phase separation of the fields with the mechanical, as well as the separate presentation of test objects to each eye, which leads to an increase in the angle of squint and reduces the tendency to binocular fusion.

 The closest analogue of the proposed method is the method of phase separation of the Alhorn fields, which formed the basis of the phase-differential haploscope of its design. The principle of operation is the separation of images of the left and right eye with the help of disc-shutters, rotating at the same speed in antiphase and located in front of each eye and in front of two projectors. The disadvantage of this method is the low separation frequency, which gives a flicker effect, a narrow field of view and the bulkiness of the device. Thus, the method is qualitatively unsatisfactory (9) and leads to a decrease in the recovery percentage of binocular vision.

 The capabilities of the above principle of phase separation of the field of view can be significantly improved using liquid crystal glasses to restore binocular vision. The possibility of using liquid crystal glasses with a variable refractive index to correct presbyopia is currently being studied (10), while the ability of liquid crystals to change the optical properties and, accordingly, the refractive index when applying an electric field is used. However, liquid crystal glasses were not used to treat strabismus (restoration of binocular vision).

 To improve the quality of binocular vision, the possibility of its restoration in case of functional disorders, as well as in a larger number of patients, it is necessary to reduce the effect of separation of visual fields (approaching binocular vision in vivo), which can be achieved by increasing the frequency of phase separation in liquid crystal glasses. The technical result of the proposed method is a significant reduction in the effect of separation of the fields of view of both eyes due to the use of liquid crystal glasses, which is necessary to approach binocular vision in vivo, the absence of flickering of the test field due to an increase in the frequency of presentation.

 The essence of the method consists in the phase separation of the visual fields using liquid crystal glasses (phase separation in these glasses is achieved by electrical signals synchronized with the reference signal of the computer, which provides alternate supply of right and left stimuli to the display), while the objects are presented with a frequency sufficient to eliminate the effect flickering.

 The method is as follows.

 The hardware-software complex ZhKOK (liquid crystal glasses - computer) is a combination of glasses with a liquid crystal shutter, a pulse generator and a diskette with a program for a standard IBM-compatible personal computer. The generator delivers impulses to the plates of the glasses in such a way that the right or left eye alternately opens. The switching frequency is 50 Hz, which obviously exceeds the critical fusion frequency of flickers of the human eye. The program recorded on a floppy disk, simultaneously with the switching of the glasses plates, gives the image either for the right or for the left eye to the monitor screen. Thus, a separate presentation of images to the right and left eye is achieved in addition to the consciousness of the observer. This allows you to explore binocular visual functions without additional separation of the visual fields of two eyes.

General research procedure
The researcher puts on a liquid crystal glasses (ZhKO) and takes the desired position in front of the monitor screen: during the study for a distance of 5 m from the screen, when examining for close - at 33 cm (and if necessary at a different required distance) from the screen. However, since a study with 5 m is very inconvenient, it is usually replaced by a study with 50 cm and the use of sphere-prism glasses (sphere + 2.0 diopters and a prism of 6.0 pr diopters with a base to the nose for each eye). This creates an optical “infinity” for the studied condition.

 The researcher enters the desired program, instructs the researched how to answer questions and records his answers using the keyboard. In some tests, the subject himself registers his answers using the keyboard or the mouse, for example, when examining the phoria, he sets the arrow in the right place on the line.

 At the end of the study, the researcher asks for the result in the computer and, if necessary, produces a printout.

1. The study of muscle balance of the eyes (phoria)
Phoria can be explored for near and far.

 Examination for near is carried out from a distance of 33 cm. The patient puts on his glasses for near (if he does not have them, then puts on a test frame with selected lenses), and on top of them are liquid crystal glasses (ZhKO). The researcher sets up a pair of images “horizontal line with a vertical stroke - a vertical arrow” on the screen and asks the researcher to use the mouse to set the arrow on the stroke. An error in the installation of the arrow corresponds to the sign and degree of horizontal heterophory. When a result is requested, a degree of heterophory in prism diopters (Santiradians) is issued. The minus sign denotes exophoria, the plus sign denotes esophoria. After horizontal, vertical phoria is measured. To do this, a pair of "vertical line - horizontal arrow" is set on the screen. The examined with the mouse sets the arrow on the same stroke. A plus sign denotes hyperphoria of the right eye, a minus sign - hypophoria.

 The study of phoria for the distance is carried out from a distance of 50 cm and with sphere-prismatic glasses (or with a test frame with a correction for ametropia installed in it, spheres + 2.0 diopters and prisms 6.0 ave diopters base to the nose). The procedure for studying phoria is the same as in the study for close.

2. The study of stereo vision
The highest function of binocular vision is stereoscopic vision or determining the relative distance of objects from the disparity of their images on the retinas of two eyes. The sensitivity of stereo vision is determined by the threshold value of the detected disparity (angular displacement) of the images of the right and left eye.

 This system uses three pairs of color figures presented separately to the right and left eye. In one of the pairs, the position of both figures coincides; in the other two, one of the figures is shifted horizontally by a certain distance. The researcher with the put on liquid crystal glasses (ZhKO) observes the screen from a distance of 33 cm. With ametropia or presbyopia under the ZhKO, he puts on his glasses.

 The researcher sequentially calls up the figures on the screen with an increasing amount of disparity and asks the researcher to name in which order the figures are located from the closest to the farthest: for example, 2-1-3, 3-2-1, etc. The researcher enters the answers into the computer. The result shows with what test the researcher begins to make mistakes. The tests have a disparity of 120 ", 60", 30 ", 20", 10 ", 5".

 Research results are recorded and used to evaluate the effectiveness of treatment.

 Exercises to restore binocular vision are playful in nature and are performed as follows.

 The patient sits in front of the computer screen at a distance of 40-50 cm. Liquid crystal glasses are put on the patient. A plot picture appears on the display screen, which the patient with glasses sees in a three-dimensional image. The patient’s task is to correctly assess the relative position of the two test objects and to carry out their correct interaction in the conditions of this game (for example, using the mouse - the “knock down target” manipulator). The transition to a more difficult level is carried out after the successful completion of the previous task. The complication of the task is expressed in a sequential decrease in the degree of disparity of the right and left images in relation to each other, and the binocular fusion of these images during the execution of visual exercises leads to a better binocular vision. The result is recorded in the form of points, during subsequent sessions, their number increases. Conducted 10 sessions of 15-20 minutes.

 Example. Patient A.P. 10 years.

 Diagnosis: operated convergent strabismus.

The strabismus angle according to Hirschberg is 5 deg., The nature of vision in the color test from 5 m, 1 m is simultaneous. At synoptophore: ОУ = СУ = +5 hail
In the study using the proposed method with wearing liquid crystal glasses by combining on the screen an arrow with a mark, the degree of heterophory +6.7 srad, min. viewing angle 2 degrees. The level of exercise on the first day is III (number of points - 202). After 4 lessons - increasing the level of completion to VI (number of points - 808).

 Conducted 10 lessons on the proposed method.

 Binocular status after treatment: the nature of vision in the color test is 1 m, 2.5 m is unstable binocular. Foria +2.8 srad., Min. angle of stereo vision - 0.5 degrees. The level of exercise - VIII (points - 1854).

 Thus, the proposed method can improve the quality of binocular functions, reduce the threshold of stereo vision and the degree of phoria, which increases the percentage of binocular vision recovery at the final stages of treatment of strabismus.

Claims (1)

 A method for studying and restoring binocular vision, including phase separation of the visual fields by presenting objects separately to the right and left eye, characterized in that the visual fields are separated using liquid crystal glasses, while the objects are presented with a frequency sufficient to exclude the flickering effect, and increase the distance to the object using sphere-prismatic glasses.