Peculiarities of Interferential Pictures of Eyes at Horizontal Heterotropy

Heterotropy is not only cosmetic aesthetic defect and also difficult in psychological focus and causes damage of binocular functions and decrease of vision. Heterotropy is widespread pathology which is present in 2-7% of population based on author's data. In Ukraine 1,2 million patients who are ill with heterotropy, and they require conservative and surgical treatment and also children aged 14 years old present group which contains more than 200. Annually about 10 thousands surgeries are performed. Heterotropy as usual has significant manifestations as one or two deviation eyes. But diagnostics of reasons which lead to these deviations can be difficult that is accompanied with difficult biomechanical interrelation of extraocular muscles. Externally similar manifestations of heterotropy can be caused by different causes. It is very difficult to determine the role of structural and functional condition of extraocular muscles but it is impossible to detect proper management of treatment. Polarization-optical method is potential which is based on property of optical anisotropy of cornea. It was established that form of interferential pictures which can be observed on eye cornea in polarized light and depends on structural and functional condition of extraocular muscles. When extraocular muscles are defected the form of interferential pictures changes and it allows using them for diagnostics. The aim of paper was to evaluate peculiarities of form of interferential pictures at horizontal heterotropy. Indices of parameters of 100 interferential pictures were analyzed and horizontal heterotropy was revealed. Cut length of diagonals of interferential rhomb and corners between these cuts were evaluated. Obscure clustering was used to evaluate peculiarities of parameters of interferential pictures depending on structural and functional condition of extraocular muscles. Division of interferential pictures on clusters was done in two stages. Division was done angularly between diagonals of interferential rhomb during the first stage, during the second one it was done lengthways of corners of horizontal diagonal. Two clusters were formed which differ the form from interferential pictures. The first cluster included 45 eyes, the second one contained 55 ones. In the first cluster eye deviation horizontally was caused by displacement of attachment of upper direct muscle from medial one in nasal direction so in 42% cases it was associated with imbalance of muscles of horizontal action. Similar imbalance can be associated with increase of one muscle on the background of impairment of another or displacement of muscles through lines of their action. Approaching of the place of insertion to limbus is proportional to its increase, removal – its decrease. Normal position of muscles is placed in the second cluster, and horizontal heterotropy is caused by imbalance of muscles' stress of horizontal action.