Strabismus in children

Strabismus is a different type of damage to the oculomotor and visual systems, in which one eye deviates from the common fixation point, leading to a disruption of monocular and binocular visual functions. In addition, strabismus is a psychologically distressing cosmetic defect. People suffering from strabismus are limited in their professional choices.

Strabismus is polyetiological in nature:

• refractive errors (hypermetropia, myopia, astigmatism); o congenital defects of binocular vision:
• diseases that lead to decreased vision or blindness in one eye;
• congenital or acquired paresis and paralysis of the oculomotor muscles;
• atypical oculomotor syndromes (Duane, Brown, Mobius syndromes, etc.).

Often, strabismus is hereditary (up to 35-40% of cases).

There are two main types of strabismus: concomitant and non-concomitant. They differ in both clinical presentation and pathogenesis.

Concomitant strabismus is a pathology predominantly of childhood. According to generalized literature data, it occurs in 1.5-2.5% of children.

In concomitant strabismus, the functions of the oculomotor muscles are not impaired, but the binocular guidance apparatus suffers, which is expressed in the violation of the vergence mechanism - convergence and divergence and a more subtle mechanism of bifixation. The mechanism of occurrence of binocular disorders in concomitant strabismus is explained by the phenomenon of retinal correspondence and the phenomenon of diplopia due to the displacement of the visual axis (during deviation) and the projection of the image of the fixation object onto the disparate area. Due to the adaptive mechanisms, which are especially easily manifested in childhood, the visual and nervous systems adapt to the asymmetric position of the eyes, and double vision is eliminated by functional inhibition in one of the monocular visual systems. This is the reason for the decrease in vision (amblyopia) in the constantly squinting eye.

Depending on the direction of deviation of the squinting eye, a distinction is made between convergent strabismus (esotropia) - deviation of the squinting eye toward the nose, divergent strabismus (exotropia) - deviation of the squinting eye toward the temple; vertical strabismus - with deviation of one eye up or down (hyper- and hypotropia). With torsional displacements of the eye (tilt of its vertical meridian toward the temple or nose), we speak of cyclotropia (ex- and incyclotropia).

In concomitant strabismus, convergent (70-80%) and divergent (15-20%) are more common. Vertical and torsional deviations occur, as a rule, in paretic and paralytic strabismus.

Incompatible forms of strabismus include paralytic, paretic strabismus, atypical oculomotor syndromes, limitations of eye mobility caused by muscle attachment anomalies, neurogenic, traumatic factors, etc.

Depending on the nature of the deviation of the eye, strabismus can be unilateral, that is, monolateral, when one eye constantly squints (about 70% of patients), and alternating, when one eye or the other squints alternately.

Monolateral strabismus is accompanied by amblyopia, i.e. decreased visual acuity of the constantly squinting eye.

Depending on the degree of visual acuity reduction, amblyopia is classified as:

• low degree - with visual acuity of the squinting eye 0.4-0.8;
• moderate - with visual acuity of 0.2-0.3;
• high degree - with visual acuity of 0.05-0.1;
• very high degree - with visual acuity of 0.04 and below (Avetisov E.S., 1968).

With alternating strabismus, the visual acuity of both eyes is usually quite high and practically the same due to alternate fixation.

According to the mechanism of development, amblyopia is divided into disbinocular amblyopia, which occurs as a result of impaired binocular vision, refractive amblyopia, in the presence of refractive anomalies (ametropia), which is a consequence of untimely or inconstant wearing of glasses; in the presence of uncorrected anisometropia (the difference in refraction between the right and left eyes), akizametropia occurs. Refractive amblyopia is quite successfully overcome with rational and constant optical correction (glasses, contact lenses).

Clouding of the ocular media (congenital cataract, leukoma) can be the cause of obscuration amblyopia, which is difficult to treat and requires timely surgical intervention (for example, extraction of congenital cataract).

Depending on the affected side, amblyopia can be right-sided, left-sided, or bilateral.

Depending on the degree of participation of accommodation in the occurrence of strabismus, a distinction is made between accommodative, partially accommodative and non-accommodative strabismus.

For accommodative strabismus (15-25%), the deviation (deviation of the eye) is eliminated with optical correction of ametropia, i.e. with constant wearing of glasses. Quite often, binocular vision is restored. Patients do not need surgical treatment. With non-accommodative strabismus, wearing glasses does not eliminate deviation, and treatment necessarily includes a surgical stage. With partial-accommodative strabismus, wearing glasses reduces, but does not completely eliminate deviation.

Strabismus can also be permanent or periodic, when the presence of deviation alternates with symmetrical position of the eyes.

The system of preventive measures includes examination by an ophthalmologist at the decreed ages, annual targeted medical examination, and protection of the mother's health during pregnancy. This ensures the possibility of timely treatment, which is especially important during the period of formation of visual functions.

Paralytic strabismus is caused by paralysis or paresis of one or more extraocular muscles, caused by various reasons: trauma, infections, neoplasms, etc. It is characterized primarily by the limitation or lack of mobility of the squinting eye in the direction of the action of the paralyzed muscle. When looking in this direction, double vision or diplopia occurs.

Paralytic strabismus

In domestic and foreign practice, a system of complex treatment of concomitant strabismus is used. Treatment should begin with the appointment of optical correction of refractive errors and constant wearing of glasses. This ensures the restoration of visual acuity and helps to eliminate or reduce the angle of strabismus.

Treatment of strabismus in children

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