Strabismus: treatment

The ultimate goal of the treatment of friendly strabismus is the restoration of binocular vision, since only under this condition visual functions are restored and asymmetry in the position of the eyes is eliminated.

They use the system of complex treatment of friendly strabismus, which includes:

• optical correction of ametropia (glasses, contact lenses);
• Pleoptic treatment (pleoptics - treatment of amblyopia);
• surgery;
• Orthotodiploptic treatment aimed at restoring binocular functions (pre- and postoperative) and deep vision.

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Optical correction of strabismus

Optical correction of ametropia helps restore visual acuity and normalize the accommodation and convergence ratio. This leads to a reduction or elimination of the angle of strabismus and ultimately contributes to the restoration of binocular vision (with accommodative strabismus) or the creation of conditions for this. Correction of ametropia is indicated for any forms of strabismus. Points should be prescribed for permanent wearing under systematic control of visual acuity (once every 2-3 months).

Pleoptics

Pleoptika is a system of methods for treating amblyopia.

One of the traditional and basic methods of pleoptical treatment is direct occlusion - turning off a healthy (fixing) eye. It creates conditions for fixing objects with a mowing eye, including it in active visual activity and in a significant number of cases, especially with a timely appointment, leads to restoration of visual acuity of the mowing eye. To this end, use special plastic occludors attached to the spectacle frame, or homemade soft curtains (curtains), as well as semi-transparent (with varying degrees of density) occludors, since for the treatment of amblyopia, it is sufficient to exclude only the uniform vision.

As the visual acuity of the amblyopic eye increases, the degree of transparency of the occludor in front of the leading eye can be increased. Semi-transparent occlusion also contributes to the development of binocular coordination of both eyes. The occlusion mode is determined by the doctor. Occlusion is prescribed for the whole day (occludor is removed at night), for several hours a day or every other day, depending on the degree of decrease in visual acuity.

It should be remembered that direct occlusion can lead to disruption of function and reduction of binocular cortical neurons, resulting in a deterioration of binocular vision, so use the tactic of a gradual transition to other methods of treatment or use of penalization. The principle of penalization (from French penalite - fine, recovery) is to create artificial anisometropia in a patient with the help of special temporary glasses. The reason for the development of the method was the observation of French researchers (Pfandi, Pouliquen and Quera) who noted that amblyopia is absent in anisometropia against a background of myopia of a weak degree of one eye and emmetropia or weak hyperopia of the other eye.

Penalization sunglasses "fine" are best seen by the eye. They are selected individually, while anisometropia is artificially created, for example, by hypercorrection (3.0 D) of a better eye with plus lenses, sometimes in combination with its atropization. As a result, the leading eye becomes myopic and its vision is deteriorated to the distance, the amblyopic eye is connected to active work by means of full optical correction. In this case, unlike direct occlusion, the possibility of vision with two eyes remains, so penization is more physiological, but it is more effective at an earlier age - 3-5 years.

In combination with occlusion, or separately apply the methods of light stimulation of the amblyopic eye: the method of local "blinding" stimulation of the central fossa of the retina, developed by ES Avetisov, the method of consecutive visual images according to the Kuppers, the luminescence of the paracentral site of the retina (eccentric fixation site) . These methods provide a disinhibitory effect and remove the phenomenon of suppression from the central zone of the retina.

The method is chosen depending on the age of the child, the features of his behavior and intellect, the state of visual fixation.

For treatment according to Avetisov's method, which can be combined with direct occlusion, various sources of brightness are used: lightguide, laser light. The duration of the procedure is several minutes, so it can be used in young children.

The method of successive images of the Küppers is based on their excitation through the illumination of the fundus, while the central fossa is simultaneously darkened by a circular test object. Consecutive visual images after the light are observed on a white screen, and their formation is stimulated by intermittent illumination of the screen. When using this method, higher demands are placed on the patient's intelligence than on Avetisov's treatment.

Treatment with these methods, as well as with the use of general light, light through the red filter and other varieties are carried out on a monobinoscope. The device allows for the fixation of the child's head to carry out examination of the fundus, visual fixation, pleoptical and diplomatic treatment under the control of ophthalmoscopy.

All of the above methods must be used in conjunction with active home visual training (drawing, playing with small details such as "Mosaic", "Lego", etc.).

Laser radiation is used in pleiotical treatment in the form of reflected laser light, the so-called speckles, by observing the laser "granularity", which has a stimulating effect on the retina. Use domestic devices "LAR" and "MAKDEL": the first - remote, the second - attach to the eyes. Laser speckles can also be used on a monobinoscope.

These methods make it possible to influence mainly the light and brightness sensitivity of the eye. Complex impact on various types of sensitivity in amblyopia is successfully carried out with the help of dynamic color and frequency-contrast stimuli of different brightness, shape and semantic content. This is implemented in special domestic computer programs "EUE" (exercises "Tire", "Chasing", "Crosses", "Spider", etc.). Exercises are interesting for children, they require their active participation. Stimulating tests are dynamic and easy to change. The principle of dynamic change of color and contrast-frequency stimuli is also used in the method based on the phenomenon of polarized light interference by AE Vakurina. The complex effect on various types of visual sensitivity significantly increases the effectiveness of pleoptotic treatment.

Surgical treatment of strabismus

With strabismus, the goal of the operation is to restore the symmetrical or close position of the eyes by changing the muscular balance. Strengthen weak or weaken strong muscles.

To the operations weakening the action of the muscles include recession (transfer of the place of attachment of the muscle posteriorly from the anatomical one), partial myotomy (application of transverse marginal incisions on both sides of the muscle), lengthening of the muscle by various plastic manipulations), tenotomy (intersection of the muscle tendon). Currently, the tenotomy is practically not used, as it can lead to a sharp limitation of mobility of the eyeball and exclude the possibility of restoring visual functions.

In order to strengthen the action of the muscle, the muscle region is resected (4-8 mm long, depending on the degree of intervention dosing and the angle of strabismus) or the formation of the muscle fold or the tendon folds of the muscle - tenorrhaphy, and the movement of the attachment site of the muscle anteriorly (anteposition). With convergent strabismus weaken the internal rectus muscle and strengthen the external rectus muscle, with divergent reverse actions.

The basic principles of performing surgical intervention with strabismus are as follows.

• It is necessary to abandon the forced interventions, to observe the principle of preliminary dosing of the operation in accordance with existing calculation schemes. The operation is performed in stages: first on one eye, then (after 3-6 months) on the other.
• Evenly distributed dosed intervention on several eye muscles (weakening the strong, strengthening weak muscles).
• Be sure to keep the muscle in touch with the eyeball during surgery on it.

Restoring the correct position of the eyes creates conditions for the restoration of binocular vision, which can provide self-correction of the residual angle of strabismus in the postoperative period. At large angles of strabismus (30 ° and more), operations are performed in 2 (or 3) stages depending on the initial angle of strabismus angle.

A high cosmetic and therapeutic effect is noted when using the dosing scheme of the operation effect developed by ES Avetisov and Kh. M. Makhkamova (1966). This scheme provides a recession of the internal rectus muscle by 4 mm with deviation in Hirschberg less than 10 °. Recession more often leads to a limitation of mobility of the eyeball. At angles of strabismus of 10 °, 15 °, 20 °, 25 ° this operation is performed in combination with resection (strengthening) of the antagonist - the external rectus muscle of the same eye - in a dosage of 4-5; 6; 7-8 and 9 mm respectively. If the residual deviation is preserved, the second stage of the operation is performed on the other eye using a similar dosing schedule no earlier than 4-6 months. Symmetrical position of the eyes is achieved in 85% of patients and more.

A similar dosing scheme is used in operations for divergent strabismus, but at the same time weaken the external muscle (make it a recession), but strengthen the internal line.

Indication for the operation is the lack of therapeutic effect with a constant (for 1,5-2 years) wearing glasses (if they are shown).

Usually, the operation is performed at the age of 4-6 years, which depends on the time of onset of the disease. With congenital forms of the disease and large angles of eye deviation, the operation is done earlier - in 2-3 years. It is advisable to eliminate strabismus in preschool age, which contributes to the effectiveness of further functional treatment and has a beneficial effect on the restoration of visual functions.

Orthoptic and diplomatic treatment of strabismus

Orthoptics and diplomacy are a system of methods for restoring binocular vision, more precisely binocular functions, whose elements are: bifoveal fusion, fusional reserves, relative accommodation, stereo effect, deep perception of space and other functions. In this case, orthoptics is a treatment on instruments with complete artificial separation of the fields of vision of both eyes: each eye is presented with a separate object and set it at an angle of strabismus; Diplomacy is a treatment in natural and close to them conditions.

Binocular exercises are performed after reaching the maximum possible visual acuity of the mowing eye, but the visual acuity is 0.3-0.4.

Orthoptic exercises are usually performed on devices with a mechanical separation of the visual fields (mechanical haploscopy), the most important of which is synoptophor (analogues - amblebifor, orthoampliophore, synoptoscope, etc.). Paired test objects for both eyes are mobile and can be located at any angle of strabismus. This is the great advantage of synoptophore in front of instruments with fixed patterns. C-naptophor has a diagnostic and therapeutic purpose. With the diagnostic purpose (definition of functional scotoma, bifoveal influence), test objects for juxtaposition ("chicken and egg") or small (2.5 ° or 5 °) test objects for fusion ("cat with tail" and "cat with ears "). To determine the functional reserves and for therapeutic purposes, test objects are used to merge large sizes (7.5 °, 10 ", etc.).

The goal of the exercises is to eliminate the functional scotoma and develop a bifoveal fusion (sensory fusion). For this, two types of exercises are used: alternating (alternating) or simultaneous light stimulation ("flashing"). Test objects should be placed under the objective angle of strabismus, then they are projected onto the central fossa of the retina. The device allows you to change the flashing frequency from 2 to 8 in 1 s, which is consistently increased during the exercise.

The third type of exercise - the development of fusional reserves: horizontal (positive and negative, ie, convergence and divergence), vertical, cyclorezervov (circular). First, large and then smaller tests are used to merge. Exercises are prescribed both in the pre- and postoperative period and are administered in courses of 15-20 sessions with an interval of 2 to 3 months.

Orthoptic devices, for all their attractiveness and necessity (at the initial stages of treatment) limit the possibility of restoring binocular functions under natural conditions and provide a cure only in 25-30% of patients, which is due to artificial conditions of vision on these devices. In this regard, after achieving a symmetrical position of the eyes, treatment should be performed to restore binocular functions in "free space", without a mechanical separation of the fields of vision.

One of these methods is the method of binocular successive images. It allows you to restore the biphosic fusion, eliminate the functional cattle and restore binocular vision. The method can be used in combination with exercises on synoptophor with a symmetrical or close to it eye position in the postoperative period. Sequential images (in the form of a circle with a right horizontal mark for the right eye and a left mark for the left eye) cause, as in the case of the Kuppers method (in the treatment of amblyopia), on a monobinoscope, but both eyes are illuminated, successively: first one and then other. Then, the images caused by each eye are observed on a white screen in case of intermittent illumination and combines them into a single image. After 1-2 min the procedure of light is repeated 2 more times. The use of the method of binocular successive images increases the effectiveness of treatment and helps to restore binocular vision.

Disadvantages of orthoptics methods have led to the development of another system of treatment - diplomacy. The main principle of diplomacy is to eliminate the phenomenon of suppressing the visual appearance of the mowing eye in natural conditions by exciting diplopia and developing a fusion reflex of bifixation.

All diploptic methods are used with two open eyes, presence, bifovial fusions, symmetrical or close to it eye position achieved by surgery or optical correction. There are a number of diplomatic methods in which various dissociating ("provocative") techniques are used to initiate diplopia.

Restoration of the bifixation mechanism by the method developed by ES Avetisov and TP Kashchenko (1976) is carried out with the help of a prism, rhythmically presented in front of one eye for 2-3 seconds with an interval of 1-2 s. The prism deflects the image of the fixation object onto the paracentral areas of the retina, which causes doubling, which is a stimulus to binocular fusion-the so-called fusion reflex (bifixation). The power of the prism is sequentially increased from 2-4 to 10-12 Dpt. A series of instruments "Diploptik", which includes a set of prisms, was developed. There are devices that allow you to change the strength of the prism and the direction of its base, then to the nose, then to the temple in automatic mode.

The method of separation of accommodation and convergence (the "dissociation" method) "teaches" binocular fusion under conditions of increasing load by negative lenses, and then under the conditions of successive relaxation by positive spherical lenses. The patient overcomes the doubling excited in this case. The method promotes the development not only of bifixation and fusion, but also of binocular (relative) accommodation, without which binocular vision is impossible. With the help of the domestic device "Forbis" it is possible to train binocular vision and relative accommodation in conditions of color, raster and polaroid separation of fields of vision.

Any diplomatic exercise is performed for 15-25 minutes, 15-20 sessions are assigned to the course. During the exercises, the binocular vision is controlled from different working distances - 33 cm, 1 m, 5 m, with glasses and without glasses. The reserves of relative accommodation are also monitored: the amount of negative spherical lenses transferred characterizes the positive reserves carried by positive lenses - negative stocks. When using the dissociation method on the color test for near 33 cm (on the Forbis device), negative reserves normally average +5.0 D, positive - up to 7.0 D; in patients at the initial stages of treatment they are much smaller and can be approximately +1.0 and -1.0 Dpt.

Diplomatic method of using color (red, green, etc.) filters of increasing density is realized with the help of special rulers - light filters. Density (or throughput) of light filters differs on average by 5%. The weakest filter - No. 1 (5% density, or high throughput - up to 95%), the densest - No. 15 (75% density).

Before one eye of the patient (with two open eyes, as with any diplomatic exercise), put a ruler with filters and ask him to fix a circular luminous test object with a diameter of 1-2 cm, located at a distance of 1-2 m. After the onset of doubling, provoked color filter, the patient must merge a slightly different image of the fixation object (for example, white and pink). Consistently increase the density of the color filter and on each of them they train binocular fusion.

For the first time a ruler with red light filters was used by the Italian scientist V. Bagolini (1966) with a diagnostic purpose. In domestic Strabology red light filters are used not only for therapeutic purposes, but also for determining the stability of the binocular vision achieved. The criterion for assessing resistance is the density (measured in percent) of the light filter at which binocular vision is violated and doubling occurs.

With a therapeutic purpose, a set of neutral (light gray), green (blue), red and yellow light filters is used. If the red filters (which are also used as diagnostic ones) are introduced with difficulty, the treatment starts with less dissociating (uncoupling) neutral filters. After achieving binocular fusion on neutral filters (all degrees of density), green or blue and then red and yellow light filters are sequentially shown. This method entered the clinical practice as a chromatic diplomacy.

For binocular training in the system of diplomatic treatment use computer programs ("EYE", "Contour"), based on the color separation of fields of view. Exercises are fascinating, playful, provide active participation of the patient.

In diplomacy, the binarimetry method is also used, consisting in the presentation of two paired test objects on a binarimeter in free space. In the process of performing the exercises, merge test objects, reducing the distance between them, drawing them closer and pushing them along the axis of the device (search for a comfort zone).

This creates a third, average binocular image - imaginary, and in depth it is located closer or further to the ring of the device and can coincide with its plane when moving the frame with test objects. These exercises develop binocular, deep perception and train relative accommodation.

There are other methods of psi doing diploptic exercises. Diplopia is caused by creating an artificial aniseicoria by increasing the size of one of the monocular images using a variable-zoom lens. Under natural conditions, the difference in the magnitude of images between the right and left eye is transferred to 5%, artificially induced aniseukonia in healthy people can be tolerated at a difference in the image size to (50-70%, and in patients with strabismus only up to 15-20%.

An original diplomatic method based on phase (in time) presentation of stimulating tests is for the right, then for the left eye.

There is an opinion that visual information is transmitted alternately - then on the right, then on the left visual channel. There is also a certain frequency ("phase") of such a transmission, which is disturbed by various pathological conditions, for example, with strabismus. This is the basis for the method of a phase haploscopy with the use of liquid crystal glasses (ZHKO). When an electric pulse passes through the plates of such glasses in a certain frequency-phase mode, their transparency changes: one glass will be transparent, the other at that moment - opaque. A high frequency of the change of such time phases in the ZHKO (more than 80 Hz), the subject does not feel. This is the advantage of the ZHKO compared to other methods of phase presentation of test objects.

These glasses are used in two versions. In the first patient should perform fascinating deep-seated exercises "hit the target" on the computer screen, on which the pictures disparately located for both eyes are created with the same frequency, which creates the effect of depth. In the process of performing exercises, the level of their complexity increases (convergence of paired drawings, reduction of depth thresholds), which contributes to the sharpness of deep vision.

In the second variant, a HOLD for wearing with an autonomous power supply system is used. In these glasses, along with the alternating phases for each eye, the binocular phase is turned on when both eyes are looking through the transparent plates of the glasses, as a result of which the trainee is gradually approaching the natural conditions of visual perception.

Diplomatic exercises compared with orthotics improve the effectiveness of treatment and contribute to a more significant recovery of binocular vision - from 25-30% (after orthoptics) to 60-65%, and with early application and more.

Deep vision and stereo vision are trained with various deep-eye devices and stereoscopes. Exercises using deep instruments (a device for pelletizing balls, a three-pronged Howard-Dolman device, a Litinsky device, etc.) are based on the presentation of a real depth difference. During the study, the patient should not see the ends of the rods of the three-rod device (moving middle and two lateral ones, standing on one transverse line). After displacement (by the researcher) of the middle rod, the patient should place it with the help of a movable knitting needle in a row with the lateral ones. By the degree of divergence of the rods determine the severity of deep vision (in degrees or linear values). In the norm, the sharpness of deep vision is 1-2 cm in the examination from 1-2 m. Deep vision is well trained in real conditions, for example, in ball games (volleyball, tennis, basketball, etc.).

The study using stereoscopes is based on the presentation of stereopair test objects with a disparity (displacement) of varying degrees. They serve to measure the severity of stereoscopic vision, which depends on the size of the test objects, the age and degree of fitness of the subject. In healthy individuals, it is 10-30 (angular seconds).

With a diplomatic treatment a certain role is given to the prismatic points. Prismatic lenses are known to refract the light beam, shifting the image of the fixation object on the retina toward the base of the prism. In the presence of small or residual angles, strabismus in the postoperative period is prescribed prismatic glasses for wearing along with diplomatic treatment. As the angle of strabism decreases, the force of the prismatic lenses is reduced, and then the glasses are canceled.

Prisms are also used to develop fusional reserves in "free space". In this case, it is convenient to use a biprism of the Landolt-Herschel type, the design of which allows smoothly increasing (or decreasing) its prismatic action by rotating the disk.

Biprism of domestic production (OKP - ophthalmic compensator prismatic) can be fixed in a special device or spectacled frame. Changing the direction of the base of the prism to the temple promotes the development of positive fusional reserves, to the nose - negative.