8-Year Outcomes of Bilateral Lateral Rectus Recessions versus Unilateral Recess-Resect in Childhood Basic-Type Intermittent Exotropia

OBJECTIVE: To report 8‐year outcomes from a randomized controlled trial (RCT) comparing bilateral lateral rectus muscle recessions (BLRc) with unilateral recess‐resect (R&R) for childhood intermittent exotropia (IXT). DESIGN: Eight‐year follow‐up of RCT cohort PARTICIPANTS: 123 of 197 randomized participants agreed to continue follow‐up after the 3‐year outcome visit (baseline age 3 to <11 years with basic‐type IXT 15‐40 prism diopters (Δ) by prism and alternate cover test (PACT), baseline stereoacuity of 400 arcsec or better, no prior surgery) METHODS: Following the RCT primary outcome at 3 years, annual follow‐up from 4 through 8 years with treatment at investigator discretion. MAIN OUTCOME MEASURES: Suboptimal surgical outcome by 8 years after randomization, defined as any of the following at any visit: exotropia ≥10Δ by simultaneous prism cover test (SPCT) at distance or near; constant esotropia (ET) ≥6Δ by SPCT at distance or near; loss of near stereoacuity by ≥0.6 log arcsec from baseline; or reoperation. Secondary outcomes included 1) reoperation by 8 years and 2) complete or near‐complete resolution at 8 years: exodeviation <10Δ by SPCT and PACT at distance and near and ≥10Δ reduction from baseline PACT at distance and near; ET <6Δ at distance and near; no decrease in stereoacuity by ≥0.6 log arcsec from baseline; no reoperation or nonsurgical treatment for IXT. RESULTS: The Kaplan‐Meier cumulative probability of suboptimal surgical outcome through 8 years was 68% (55 events among 101 at risk) for BLRc and 53% (42 events among 96 at risk) for R&R (difference = 15%, 95% CI: ‐2% to 32%, P = 0.08). Complete or near‐complete resolution at 8 years occurred in 14% (6/42) for BLRc and 37% (16/43) for R&R (difference = ‐22%, 95% CI: ‐44% to ‐0.1%, P = 0.049). The cumulative probability of reoperation was 30% for BLRc and 11% for R&R (difference = 19%, 95% CI=2% to 36%, P = 0.049). CONCLUSIONS: Despite no significant difference at primary outcome, the 95% CI did not exclude a moderate benefit of R&R, which together with secondary outcomes, suggests that unilateral R&R followed by usual care may yield better long‐term outcomes than BLRc followed by usual care, for basic‐type childhood IXT, using our surgical doses.