Effects of ptosis surgery on Schlemm canal and anterior chamber angle parameters assessed by anterior segment OCT.

Abstract

Purpose: To evaluate changes in anterior segment morphology using anterior segment optical coherence tomography (AS-OCT) in patients undergoing levator surgery for ptosis and to investigate the potential influence of eyelid position changes on anterior segment parameters.

Methods: This study included 20 eyes of 18 patients who underwent levator surgery for ptosis. Eyelid parameters (MRD-1 and palpebral fissure height) and anterior segment measurements obtained by AS-OCT were recorded preoperatively and at postoperative weeks 4-6. Angle opening distance (AOD), trabecular iris space area (TISA), iridocorneal angle (ICA), Schlemm canal length (SCL), and Schlemm canal area (SCA) were measured in nasal and temporal quadrants.

Results: Postoperatively, MRD-1 and PFH increased statistically significantly (p < 0.001 for both). Among anterior segment parameters, a significant postoperative decrease was observed only in nasal SCL (p = 0.008), with a moderate-to-large effect size (r = 0.419). No significant differences were detected in AOD, TISA, ICA, or SCA measurements in either nasal or temporal quadrants (p > 0.05). Nasal ICA demonstrated a borderline postoperative increase (p = 0.086; r = 0.271). Correlation analysis revealed a significant negative association between nasal AOD change and both MRD-1 and PFH changes.

Conclusion: Levator surgery for ptosis may be associated with subtle anterior segment morphologic changes detectable by AS-OCT. In particular, the observed decrease in nasal SCL should be regarded as an exploratory, hypothesis-generating finding that requires confirmation in larger studies.