[Surgical treatment of vertical strabismus. Part 1. Classification and diagnostics]

Vertical strabismus caused by hyperfunction of the inferior oblique muscle is a common oculomotor disorder. It is found in one third of all patients with strabismus, and in 70% of cases it is combined with esotropia. To date, there is no single approach to determining the degree of hyperfunction of the inferior oblique muscle, and the most common classifications are very subjective and inaccurate. Thus, in connection with the need to understand the severity of the disease, as well as to determine the tactics of treatment and prognosis of the surgical outcomes, it is necessary to standartize the classification of this pathology. The mechanism of action of the inferior oblique muscles of the eye is very complex and depends on the position of the eyeball at the time of their contraction. In addition to horizontal and vertical movements, they provide torsional movement. Any impairment of these muscles leads to the development of not only vertical strabismus, but excyclotropia that reduces the effectiveness of strabismus treatment. To identify all the symptoms associated with hyperfunction of the inferior oblique muscle, taking into account the peculiarities of its triple action, it is necessary to conduct a thorough diagnostic study.