A comparison of surgical techniques for the treatment of acquired esotropia with increased accommodative convergence/accommodation ratio

The conventional surgical treatment for acquired esotropia with increased accommodative convergence/accommodation ratio consists of bilateral medial rectus recessions of graded amounts based on the distance deviation while wearing full hyperopic correction. This retrospective study was undertaken to determine whether surgery was more successful when performed for the distance or near deviation measured through the distance correction. Surgical success was evaluated by 1) long-term motor alignment of ≤10 prism diopters of eso- or exotropia at distance and near, 2) sensory fusion as determined by Worth 4-Dot at 33 cm and Randot II stereo acuity testing, and 3) the continued need for bifocal or spectacle correction. Nine patients underwent surgery for their distance deviation measured with full hyperopic correction; all (100%) were successful by alignment and eight of nine (89%) by sensory criteria. Twenty-five patients underwent surgery enhanced by 1.0 to 6.5 mm per eye over the dose of surgery for the distance angle (average 3.1 mm); 20 of 25 (80%) were successful by alignment criteria and 21 of 25 (84%) were successful by sensory criteria. Two of nine patients (22%) in the distance target angle group and 13 of 25 patients (52%) in the near target angle group were able to discontinue spectacles and maintain satisfactory alignment. Six of nine (67%) patients in the distance angle group were able to discontinue bifocals, while every patient in the near angle group was so benefited. No patient in the distance target angle group, but two patients in the near target angle group, required a second operation. The near angle measured through the distance correction may be used to determine the target angle for acquired esotropia surgery. Use of this angle reduces the need for continued spectacle use, but with a risk of overcorrection.