Repeatability of Anterior Segment Measurements Using Anterior Segment OCT Combined with Placido Corneal Topography in Dry Eye Patients.

PURPOSE: To evaluate the repeatability of anterior segment parameters using the MS-39 in patients with dry eye disease. METHODS: This prospective cross-sectional observational study included 52 eyes from 26 participants with dry eye disease. Each eye underwent three consecutive MS-39 acquisitions within 15 minutes. Repeatability was analyzed using the coefficient of repeatability, coefficient of variation, intraclass correlation coefficient, and repeated-measures analysis of variance. RESULTS: Most parameters showed excellent intra-session repeatability (intraclass correlation >0.98, coefficient of variation <15%), except corneal astigmatism (coefficient of variation approximately 52%). Exploratory stratified analyses suggested lower repeatability in eyes with higher Ocular Surface Disease Index scores and lower Tear Break-Up Time values, particularly for corneal astigmatism. CONCLUSION: The MS-39 demonstrates high intra-session repeatability for most anterior segment parameters in dry eye disease. Corneal astigmatism showed greater variability; therefore, astigmatism readings should be interpreted cautiously in patients with ocular surface instability. This study assessed intra-session repeatability only and did not evaluate inter-session reproducibility or performance relative to healthy controls.