Divergent strabismus

Exotropia (manifest exotropia) can be constant or periodic.

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Types of divergent strabismus

Constant divergent strabismus

• congenital
• sensory
• secondary

Periodic divergent strabismus

• main
• weakness of convergence
• excess of divergence

Congenital divergent strabismus

Congenital divergent strabismus is present at birth, unlike infantile esotropia.

Symptoms of congenital divergent strabismus

• Normal refraction.
• Large constant angle.
• May be accompanied by a DVD.

Neurological disorders are often associated, unlike infantile esotropia.

Treatment is primarily surgical and involves bilateral recession of the external rectus muscles, usually combined with resection of one or both internal rectus muscles, depending on the magnitude of the angle.

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Other types of divergent strabismus

Sensory divergent strabismus occurs as a result of unilateral or bilateral reduction in visual functions due to acquired diseases, such as cataracts or other opacities of the optical media in children over 5 years of age or in adults. Treatment consists of eliminating the cause of vision loss (if possible), and surgical methods are used if necessary.

Secondary divergent strabismus after surgical correction of esodeviation.

Periodic divergent strabismus

It manifests itself most often at the age of 2 years as exophoria, which develops into divergent strabismus under conditions of weakened control, in bright light, leading to a reflex closure of the deviating eye, in case of weakness or illness. Over time, the deviation becomes less controllable.

Clinical variants

• basic type: the angle of deviation when fixing a distant object is equal to the angle of deviation when fixing a close object;
• Weak convergence in older children and adults. The angle of deviation is greater when fixating a close object. May be associated with acquired myopia;
• excess of divergence, in which the angle of deviation is greater when fixing a distant object. Can be true or simulated.
  • With the true type, the angle when fixating a close object is always smaller than a distant one.
  • The simulation is accompanied by a high AC/A index. The angle becomes equal when fixing near and far objects, when
    measuring again through a +3.0 D lens, or after a short-term unilateral occlusion.

Treatment of divergent strabismus

1. Spectacle correction in patients with myopia can in some cases lead to a decrease in deviation, stimulating accommodation and, at the same time, convergence.
2. Orthoptic treatment of divergent strabismus, which involves occlusion, avoidance of double vision, and improvement of fusional convergence, can be effective.
3. Surgical treatment of divergent strabismus is necessary in most patients around the age of 5 years. Some specialists are proponents of bilateral recession of the lateral rectus muscles; others, on the contrary, recommend bilateral intervention only for patients with excess of divergence, preferring recession and resection at equal angles of deviation in fixation of near and distant objects.