Surgical management of clinically significant hypertropia associated with exotropia

To report the surgical treatment of hypertropia coexisting with exotropia, with either vertical offset surgery or additional vertical muscle surgery simultaneous to correction of the exotropia.

A total of 35 patients with exotropia and hypertropia who underwent a horizontal muscle surgery for exotropia were included. To determine efficacy in resolving a vertical deviation in patients with exotropia, 28 patients were compared in 2 groups: those who underwent horizontal muscle surgery with vertical offset and those who underwent horizontal muscle surgery with additional vertical muscle surgery. An additional 7 patients who had exotropia and hypertropia but did not undergo vertically corrective surgery were included for comparison.

Vertical offset of horizontal rectus muscles (4 mm) resulted in 8(Delta) correction of the distance hypertropia. Vertical rectus muscle recession used in the treatment of larger hypertropic deviations with exotropia had a 3(Delta) correction per 1 mm of recession. Success rates for hypertropia correction were similar between groups, 63% vertical offset and 71% vertical muscle groups; overcorrections occurred in 29% of the vertical muscle group. The vertical correction in both groups was stable in 88% over 6 months postoperatively.

Vertical offset of the horizontal muscles simultaneous with exotropia correction has a beneficial effect in small-angle hypertropia (<14(Delta)). Vertical rectus muscle surgery in patients with hypertropia greater than 10(Delta) had equivalent success; however, in intermittent exotropia the hypertropia was prone to overcorrection.