Comparison of surgical outcomes of slanted procedure for exotropia with convergence insufficiency according to their response to preoperative monocular occlusion

Abstract

The aim of this prospective study was to compare surgical outcomes of slanted bilateral lateral rectus (LR) recession for intermittent exotropia (IXT) with convergence insufficiency (CI) according to their response to preoperative monocular occlusion. This prospective study included 55 children who underwent slanted bilateral LR recession for IXT with CI. Patients were divided into two groups according to their response to preoperative monocular occlusion for 2 hours. The True CI group was defined as having near-distance differences of ≥10 PD before and after occlusion; the Masked CI group as having near-distance differences of <10 PD and ≥10 PD prior to and after occlusion. Slanted procedure reduced distance and near exodeviations from 32.1 PD and 43.0 PD to 3.5 PD and 4.4 PD, and collapsed near-distance differences from 10.9 PD to 1.0 PD at 3 years postoperatively. Cumulative probabilities of surgical success were 76%, and the mean recurrence was 50 months at 3 years postoperatively; the True CI and Masked CI groups showed cumulative success rates of 89% and 55%, respectively (p = 0.0052). Patients in the True CI group demonstrated surgical outcomes superior to those demonstrated by patients in the Masked CI group after slanted bilateral LR recession.

Figure 1

Kaplan-Meier survival plots and cumulative probabilities of success at 3 postoperative years according to life-time analysis of all the subjects in this study as well as of the two groups of intermittent exotropia with convergence insufficiency according to their response to diagnostic monocular occlusion for 2 hours. The overall cumulative probability of surgical success at 3 postoperative years was 76%. Mean recurrence was 49.9 ± 2.5 months (95% confidence interval, 44.980–54.737) in all the subjects with intermittent exotropia with convergence insufficiency. Cumulative probabilities of surgical success at 3 postoperative years were 89% in the True-CI group and 55% in the Masked-CI group. Mean recurrence in the True CI group was 55.7 ± 2.0 months (95% confidence interval, 51.725–59.658), and that in the Masked CI group was 39.6 ± 5.0 months (95% confidence interval, 29.790–49.443). There was a statistically significant difference in survival curves between the two groups. (p = 0.0052, Log-rank test).