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

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

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

Results: 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.

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