Comparison of ocular surface changes after medial rectus resection versus plication.

Purpose: To measure the surface change, after medial rectus (MR) resection or plication, with anterior segment optical coherence tomography (ASOCT), and to evaluate associated changes in ocular surface parameters.

Methods: A randomized, interventional study was conducted on 126 patients with primary exotropia with deviation between 35 and 55 PD. Patients underwent lateral rectus recession, with either MR resection (n = 63) or plication (n = 63). Conjunctival-scleral thickness (CST) was measured with ASOCT at 4 mm and 5.5 mm from the scleral spur (corresponding to the location of MR insertion and tendon, respectively). Tear meniscus height (TMH), noninvasive tear breakup time (NIBUT), and meibomian gland morphology (by infrared meibography) were evaluated. The OSDI questionnaire (Ocular Surface Disease Index) was administered. All parameters were evaluated preoperatively and 1, 2, 4 and 6 months postoperatively.

Results: While both procedures increased tissue thickness at the surgical site, the magnitude of difference between plication and resection was minimal. At 6 months, the absolute difference in CST at the muscle insertion was only 0.04 +/- 0.03 mm, a margin that is not clinically significant. Tear film markers (TMH and NIBUT) showed small, transient shifts that approached the limits of measurement variability. Subjective OSDI scores peaked at 1 month in both groups - consistent with mild postoperative discomfort - but returned to or improved beyond baseline by 6 months.

Conclusion: Both MR resection and plication cause short-lived ocular surface changes after surgery. Although plication results in a statistically thicker tissue profile, the effect size is too small to impact tear film stability or patient comfort, suggesting that concerns regarding ocular surface irregularity should not preclude the use of plication surgery.