Slanted versus conventional bilateral lateral rectus recession in children with convergence insufficiency intermittent exotropia: A multicentre, randomized trial.

PURPOSE: To assess the efficacy of slanted bilateral lateral rectus recession (S-BLR) versus conventional bilateral lateral rectus recession (C-BLR) in children with convergence insufficiency intermittent exotropia (CI-IXT).

DESIGN

Multicentre, randomized controlled trial.

METHODS

Chinese children aged 5-12 years with CI-IXT were consecutively enrolled, and randomly assigned (1:1) to receive either S-BLR or C-BLR. The primary outcome was the 12-month overall success rate, defined as a postoperative residual deviation between 10Δ of exodeviation and 5Δ of esodeviation with near-distance disparity (NDD) < 10Δ.

RESULTS

A total of 200 participants were enrolled, and 188 (97 S-BLR, 91 C-BLR) were finally included in the modified intention-to-treat analysis. The median age was 8 (6-9) years, and 90 (48 %) were male. The 12-month overall success rates did not differ significantly between the groups (group difference 8 %, P = 0.27, adjusted P = 0.36). However, S-BLR exhibited a lower rate of near undercorrection (group difference -12 %, P = 0.06), more collapse of NDD (-2.00Δ, P = 0.001), less residual near exodeviation (-4.00Δ, P < 0.001), better control of near exodeviation (0.00, P = 0.01), and a higher proportion of improved stereoacuity (12 %, P = 0.06). Subgroup analysis for NDD≤ 15Δ revealed a higher success rate of near deviation (86 % versus 69 %, P = 0.02), and a lower rate of near undercorrection (13 % versus 30 %, P = 0.01) in S-BLR group. Aside from undercorrection and overcorrection, no additional long-term suboptimal surgical outcomes were observed.

CONCLUSIONS

Although the overall success rates did not differ, S-BLR showed potential superiority at near in children with CI-IXT. More participants with NDD> 15Δ, and a longer follow-up are needed to validate these findings.