Comparison between bilateral lateral rectus recession and bilateral primary medial rectus resection in basic type intermittent exotropia.

Purpose

To compare the outcomes of bilateral lateral rectus recession (BLRc) and bilateral primary medial rectus resection (BMRs) for the management of basic type intermittent exotropia (IXT).

Methods

This prospective, randomized, controlled study, included 38 children with basic type IXT with an angle of deviation of 20Δ-40Δ treated at a single institution from June 2023 through January 2025. Patients were divided into two groups: the BLRc group and the BMRs group. Angles of deviation, ductions, versions, sensory functions, and vertical palpebral fissure height (PFH) were evaluated 6 months after surgery. Success was defined as orthophoria or deviation between exotropia/phoria ≤10Δ and esotropia/phoria ≤5Δ

Results

Mean patient age at time of surgery was 6.8 ± 2.3 years in the BMRs group and 7.0 ± 2.5 years in the BLRc group. At the 6-month follow-up, success was higher in the BLRc than in the BMRs group (70% vs 55.5% [P = 0.564]), and the mean postoperative angle of deviation was higher in the BMRs group than in the BLRc group (10Δ vs 1Δ [P < 0.01]). Undercorrection was more common in BMRs group (44% vs 20%), whereas overcorrection was more common in BLRc group (10% vs 0%). There was an improvement of 0.336 log arcsec in near stereoacuity; however, only 20% of cases showed an improvement of >2 octaves. Moreover, the difference in improvement between both groups was statistically insignificant. There was no significant change in the PFH in either group.

Conclusions

Both surgeries can effectively manage basic type IXT, but BMRs may be more prone to undercorrection by 6 months postoperatively.