The 17 patients reported in this study all had an A-pattern with exotropia in the lower field of gaze prior to bilateral superior oblique tenectomy. The maximum correction obtained in the lower field of gaze was 33Δ, minimum correction 5Δ and average correction was 20Δ. The A-pattern was corrected in 13, improved in 3, and unchanged in 1 of the 17 patients. Of 34 overacting superior oblique muscles, 17 were corrected, 9 were improved, 6 were unchanged, and 2 became worse. In no case did underaction of the superior oblique muscle develop after tenectomy.
Bedrossian EH. Bilateral Superior Oblique Tenectomy for the A-pattern in Strabismus. Arch Ophthalmol. 1967;78(3):334-336. doi:10.1001/archopht.1967.00980030336013