Bilateral Lateral Rectus Muscle Recessions Versus Recess-Resect for Childhood Intermittent Exotropia (IXT): 8-year Outcomes

Abstract

Purpose : In a randomized clinical trial comparing bilateral lateral rectus muscle recessions (BLR) with unilateral recess-resect (R&R) for childhood intermittent exotropia (IXT), we previously found no significant difference in cumulative probability of suboptimal surgical outcome by 3 years (46% in BLR and 34% in R&R; difference = 9%; 95% confidence interval (CI): -6% to 23%). (PEDIG, Ophthalmology 2019;126(2): 305-317) We now report outcomes after 8 years of follow-up.

Methods : After a 3-year randomized trial, 123 (64 in BLR and 59 in R&R) of the 197 original cohort (age 3 to <11 years with basic-type IXT 15 to 40 prism diopters (Δ), stereoacuity of 400 arc sec or better and no prior surgery), consented to participate in an additional 5 years of follow up, with treatment at investigator discretion. The primary outcome measure was “suboptimal surgical outcome” by 8 years, defined as any of the following at any visit: exotropia ≥10Δ by simultaneous prism cover test (SPCT) at distance or near; constant esotropia ≥6Δ by SPCT at distance or near; loss of near stereoacuity by ≥2 octaves from baseline; re-operation without meeting any of aforementioned criteria. "Complete or near complete resolution" at 8 years was defined as: any exodeviation <10Δ by SPCT and prism alternate cover test (PACT) at distance and near AND ≥10Δ reduction in baseline angle by PACT at distance and at near (if ≥10Δ at baseline); any ET <6 Δ at distance and near; no decrease in stereoacuity by ≥2 octaves; and no additional treatment for IXT.

Results : The cumulative probability of suboptimal surgical outcome by 8 years was 66% for BLR and 53% for R&R (difference = 13%, 95% CI: -4% to 30%). Complete or near complete resolution at 8 years occurred in 14% (6 of 42) for BLR and 39% (16 of 41) for R&R (difference = -25%, 95% CI: -44% to -5%). The cumulative probability of reoperation by 8 years was 32% for BLR versus 10% for RR (difference = 22%, 95% CI = 7% to 37%).

Conclusions : There was no significant difference in the study-defined suboptimal surgical outcome by 8 years between BLR and R&R for childhood IXT. However, the R&R group had a higher resolution rate and lower rate of reoperation by 8 years. Taken together, our findings suggest that a unilateral recess-resect procedure may provide superior long-term outcomes to bilateral lateral rectus recession for basic-type childhood IXT.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.