Use of the four-diopter base-in prism test in microexotropia

Unilateral medial rectus resection in the treatment of small-angle exodeviation

Twenty-six patients with small-angle constant or intermittent exotropia of up to 7 degrees, and eight patients with small-angle exophoria of the convergence-insufficiency type, underwent unilateral medial rectus resection. Of the 34 patients, 9 were cured, 19 improved and in 6 surgery failed or there was early recurrence. Improvement occurred usually in patients who had basic microexotropia and in some who had homonymous abnormal retinal correspondence, a factor which limited the sensory results. The sensory, motor, and mechanical factors influencing the procedure are discussed in detail. The resection technique employed is reviewed, demonstrating the advantage of well-controlled results. This paper shows that resecting the medial recti is useful, not only in convergence insufficiency, but also in related small-angle exodeviations, for which a classification is proposed.