Abstract
PURPOSE: Consensus is lacking around optimal surgical strategies to correct V-pattern exotropia (VXT). This study quantitatively examined alternative surgical strategies and dosing . DESIGN: Comparative interventional case series. METHODS: Consecutive patients with VXT undergoing strabismus surgery between 2014 and 2025 were reviewed. Incomitance of at least 15D between sursumversion and deorsumversion was considered V-pattern. Surgeries were performed by 2 surgeons using identical technique. The primary outcome was the surgical alignment effect. RESULTS: A total of 55 patients (36 children and 19 adults) underwent horizontal rectus muscle surgery: inferior oblique (IO) recession (n = 12), superior transposition of lateral rectus muscles (n = 20), their combination (n = 10), and no modifications (n = 13). Surgery reduced average primary gaze exotropia in all groups from 29 ± 11Δ to 8 ± 8Δ (SD P < .001), irrespective of pattern collapse. There was 6.0 Δ mean postoperative exodrift after 2.1 ± 2.0 years following surgery. Pattern decreased in all groups from: 22 ± 8Δ to 10 ± 8Δ by IO recession, 22 ± 6Δ to 3 ± 6Δ by horizontal rectus transposition, 30 ± 10Δ to 5 ± 13Δ by the combination, and 16 ± 2Δ to 6 ± 7Δ with no modifications. The combined procedure yielded the greatest pattern reduction. Transpositions of half and three-quarter tendon width yielded similar effects on pattern. Linear regression showed a significant correlation between lateral rectus recession and exotropia reduction (P < .001), accounting for 40% of variance. However, the surgical effect was smaller than that predicted by Parks tables. CONCLUSIONS: IO recession, LR transposition, and their combination reduce pattern in VXT, with the greatest effect when combined. Horizontal rectus recession alone also reduces the pattern, albeit to a lesser extent. Horizontal rectus recession dose need not be adjusted for pattern collapse. Early overcorrection is recommended.