Bilateral Lateral Rectus Recession versus Unilateral lateral Rectus Recession-Medial Rectus Resection in Treatment of Basic Intermittent Exotropia

Objectives: To compare the surgical effectiveness and postoperative alignment stability of Bilateral Lateral Rectus Recession (BLR) versus Unilateral Lateral Rectus Recession combined with Medial Rectus Resection (RR) in the management of basic intermittent exotropia (IXT).Methods: A prospective randomized interventional study was conducted on 40 cases with basic IXT at Benha University Hospital. Participants were equally allocated into two groups: BLR group (n=20) and RR group (n=20). Pre- and postoperative assessments included measurement of near and far deviation angles using prism and alternate cover test, stereopsis evaluation, and visual acuity. Follow-ups were conducted at 1, 3, and 6 months postoperatively. Surgical success was defined as alignment within 10 prism diopters (PD) of orthophoria. Results: Both groups demonstrated significant reductions in near and far deviation from baseline at all follow-up points (P < 0.001). At 6 months, the RR group showed substantially lower median near deviation (0 PD [range -10 to 20]) compared to the BLR group (7 PD [range -10 to 30], P = 0.028). Far deviation was also substantially lower in RR group (0 PD vs. 9 PD, P = 0.041). Surgical success was achieved in 70% of RR group and 65% of BLR group (P = 0.361). Multivariate regression identified the RR technique as a significant predictor of improved far deviation at 6 months (B = -6.624, P = 0.038).Conclusion: Both BLR and RR are effective for managing basic IXT. However, RR demonstrated superior outcomes in reducing ocular deviation and maintaining alignment stability at six months postoperatively.