Unilateral superior oblique paresis: deviation patterns and surgical indications

To analyze different patterns of vertical strabismic deviations seen in unilateral superior oblique (SO) paresis, and the response to surgical treatment, in order to discern the most effective surgical indication to treat each clinical pattern.

A retrospective analysis of 110 patients with a diagnosis of unilateral SO paresis studied according to the follow protocol: a) Hypertropia (HT) measurement with alternate prism and cover test in the 9 diagnostic gaze positions; b) Determination of the deviation pattern; and c) Analysis of the results achieved with various surgical procedures.

We found that unilateral SO paresis presented with 3 patterns of HT: 1) Patients with marked incomitance between opposite lateroversions; 2) Cases with HT equal to or greater than 20 prism diopters in primary gaze position, lower incomitance between opposite lateroversions and incomitance in up- and downgaze; and 3) A pattern of vertical deviation characterized by a strong tendency to comitance in the 9 diagnostic gaze positions, with an overtly positive Bielschowsky Head Tilt Test and extorsion of the affected eye.

This study provides guidelines to discern the most effective surgical indication for patients with unilateral SO paresis on the basis of the presenting hypertropia pattern.