To evaluate the efficacy of monocular slanted lateral rectus (LR) muscle recession for exotropia with convergence insufficiency.

Twenty five patients with exotropia greater at near than at versus far distance by ≥10 prism diopters (PD), were divided into two groups: 15 patients who underwent monocular slanted LR recession (study group), and 10 patients who underwent monocular standard LR recession (control group). In the study group, the lower horn of the LR was recessed according to near deviation, the upper horn was recessed according to distance deviation. In the control group, monocular LR was recessed according to distance deviation. The postoperative ocular alignment at distance and near, and the difference between them, were measured and compared retrospectively. The criteria for successful outcome were postoperative residual deviation at near and distance, and the difference of 8 PD or less between the two.

The mean distance deviation showed a significant postoperative reduction in both groups (P<0.001, P<0.001). The mean near deviation showed a significant postoperative reduction in both groups (P<0.001, P<0.001). The mean difference between near and distance deviation showed a significant postoperative reduction only in the study group (P<0.001, P=0.175). Successful outcome was obtained in 13 our of 15 (86.7%) patients in the study group, in 2 out of 10 (20%) patients in the control group. None of the study patients had postoperative diplopia.

Monocular slanted lateral rectus recession is effective in reducing both distant and near exodeviation and in collapsing the difference between distance and near deviation them at postoperative 4 months.