Relationship between Control Grade, Stereoacuity and Surgical Success in Basic Intermittent Exotropia

PURPOSE This study was conducted to identify the relationship between control grade, stereoacuity and surgical success in basic intermittent exotropia. METHODS This retrospective study involved 44 basic intermittent exotropia patients who underwent strabismus surgery and completed at least 6 months of follow-up. The 44 patients were divided into three subgroups according to their control grade: group 1 (good control group, n = 12), group 2 (fair control group, n = 18), and group 3 (poor control group, n = 14). Evaluation was done to identify the relationships between near and distance stereoacuity and control grade, and between surgical success and control grade. Surgical success was defined as ocular alignment between 5 prism diopters esodeviation and 10 prism diopters exodeviation in the primary position at the final visit. RESULTS Mean near stereoacuity measured by the graded circle test was 57.50 seconds of arc (seconds) in group 1, 77.77 seconds in group 2, and 131.43 seconds in group 3 (p < 0.01). Mean distance steroacuity measured by Mentor B-VAT II BVS contour circle was 108.33 seconds in group 1, 148.33 seconds in group 2, and 262.82 seconds in group 3 (p < 0.01). Ten patients (83.33%) in group 1, 12 (66.67%) in group 2, and 9 (64.29%) in group 3 obtained surgical success (p = 0.28). CONCLUSIONS In basic intermittent exotropia, better control grade was significantly accompanied by better stereoacuity. Better control grade was accompanied by higher surgical success rate but with no statistical significance.