Monocular Slanted Lateral Rectus Recession for Exotropia with Convergence Insufficiency

PURPOSE: To evaluate the efficacy of monocular slanted lateral rectus (LR) muscle recession for exotropia with convergence insufficiency. METHODS: Twenty five patients with exotropia greater at near than at versus far distance by > or =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. RESULTS: 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. CONCLUSIONS: 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.

The Prospective Comparison of Surgical Outcomes in Convergence Insufficiency Exotropia

PURPOSE: The surgical results for exotropia with convergence insufficiency have been reported to be unsatisfactory and there was a risk of creating diplopia due to postoperative esotropia at distance. The purpose of this study is to determine the effective surgical method in convergence insufficiency exotropia. METHODS: Two surgical procedures were alternately performed in patients with convergence insufficiency exotropia. Minimum follow-up was 6 months after surgery. In the bimedial resection (BMR) group (n=9), bilateral medial recti (MR) resections were performed with slanted procedure where the upper MR margin was resected to correct the distance deviation and the lower margin was resected to correct the near deviation. The recession and resection (R and R) group (n=15) involved MR resection and lateral rectus recession where the amounts of resection and recession were based on the near and distance deviation, respectively. RESULTS: At an average last follow-up of 22 months, a significant reduction in the distance and near angle of deviation, as well as in the difference between the distance and near deviation, was shown in the R and R group as compared with the BMR group (p<0.05). Fresnel prism was used to treat postoperative diplopia in only one patient of the R and R group. CONCLUSIONS: The surgical method of the R and R group appeared to produce a more favorable result than that of the BMR group without the risk of long-term postoperative diplopia at distance in convergence insufficiency exotropia.