The Effect of Unilateral Lateral Rectus Recession for the Treatment of Moderate-Angle Exotropia

ABSTRACT

PURPOSE: To evaluate the surgical results and the amount of correction per millimeter after unilateral lateral rectus recession for moderate-angle exotropia in a pediatric population. METHODS: This study included 30 subjects who underwent 9-mm unilateral lateral rectus recession for basic type intermittent exotropia with deviation of 23 to 28 prism diopters (PD) and were followed-up for 6 months or more after surgery. RESULTS: Seventeen subjects were male and 13 were female. The mean age of subjects was 9.7 years. Defining satisfactory postoperative ocular alignment as 8PD or less, 25 of 30 subjects (83.3%) were satisfactorily aligned at 2 months postoperatively. The success rates at 4, and 6 months postoperatively were 76.7% respectively. No overcorrected subjects were found after 2 months postoperatively. A postoperative limitation of abduction was not found in all subjects after 2 months postoperatively. The average amount of correction per millimeter of recession at 2, 4, and 6 months was 2.83+/-0.26PD, 2.75+/-0.37PD, and 2.72+/-0.44PD respectively (range, 1.56 to 3.18PD). There was no statistically significant difference in the amount of correction per millimeter throughout the follow-up period (ANOVA, p=0.05). CONCLUSIONS: Unilateral lateral rectus recession appears to be an effective surgical procedure for the treatment of moderate-angle exotropia. However to reduce the rate of undercorrection, which is one of disadvantages of this procedure, proper patient selection is required.