Management of large V-pattern exotropia with minimal or no inferior oblique overaction

To compare the outcomes of patients with large V-pattern exotropia and minimal inferior overaction who underwent bilateral lateral rectus recession combined with full-tendon-width upward transposition of the lateral rectus muscles or bilateral inferior oblique myectomy.

The medical records of consecutive patients with V-pattern exotropia (at least 20(Δ) greater in upgaze than in downgaze) with minimal inferior oblique overaction who underwent either of the above procedures and who had at least 6 months' follow-up were retrospectively reviewed. Pre- and postoperative ductions, versions, pattern strabismus, stereoacuity and fundus torsion were analyzed. Success was defined as esophoria <8(Δ)/tropia ≤5(Δ) to exophoria/tropia ≤8(Δ) in primary gaze.

A successful outcome was achieved in 9 patients (56%) in the transposition group and 13 (72%) in the myectomy group (P = 0.48). Reduction of V pattern to <10(Δ) was achieved in 7 cases (44%) in the transposition group and 14 (78%) in the myectomy group (P = 0.04), with mean reductions of 16(Δ) ± 5(Δ) and 25(Δ) ± 5(Δ), respectively (P = 0.03). In the myectomy group, 4 patients (22%) had overcorrection with consecutive A patterns of 2(Δ)-6(Δ).

In patients with a V pattern exotropia and minimal inferior oblique over action, bilateral lateral rectus recessions plus bilateral inferior oblique myectomy can successfully eliminate the V pattern but the surgery may occasionally result in overcorrection with consecutive A pattern.