Strabismus surgery for patients with acquired nonaccommodative esotropia based on monocular occlusion test

To evaluate the outcome of surgery based on a monocular occlusion test in patients with acquired nonaccommodative esotropia (ANAET).

Patients with ANAET in which the angle of esodeviation increased by at least 10^Δ after 1 hour of monocular patching were enrolled prospectively.

A monocular occlusion test was performed for 32 patients, of whom 14 patients showed significant change in the angle of esotropia. The mean age was 21.4 (range, 5-50) years, and 8 (57%) were females. The mean spherical equivalent was 0.24 D for right eyes and 0.35 D for left eyes. The mean angle of esotropia before occlusion was 9.9^Δ ± 6.4^Δ (range, 2^Δ-20^Δ) for distance and 13.8^Δ ± 6.6^Δ (range, 4.5^Δ-25^Δ) for near. The mean angle of esotropia after monocular occlusion was 22.3^Δ ± 5.1^Δ (range, 12^Δ-30^Δ) for distance and 24.6^Δ ± 6.2^Δ (range, 12^Δ-32.5^Δ) for near. Bimedial rectus muscle recession was performed for all the patients according to near esotropia after 1 hour of monocular occlusion. Patients were followed for 12 months. Final mean angle of esodeviation was 1.0^Δ ± 2.2^Δ (range, 0^Δ-6^Δ) for distance and 3.6^Δ ± 3.2^Δ (range, 0^Δ-10^Δ) for near. But for a single case, patients achieved alignment <8^Δ of esodeviation after surgery. There was no report of diplopia or other complications postoperatively.

The findings advocate incorporating monocular occlusion into the preoperative assessment to determine the surgical target in ANAET patients.