Comparison of two measurements for the lower lid margin thickness: vernier micrometer and anterior segment optical coherence tomography.

Purpose: To investigate the reliability of using anterior segment optical coherence tomography (AS-OCT) to measure the lower lid margin thickness (LLMT) from the posterior lash line to the Marx's line by comparing with a vernier micrometer.

Methods: This was a prospective, single-center, diagnostic test study. Sixty volunteers aged between 20 and 79 without ocular diseases were recruited. A vernier micrometer and AS-OCT were, respectively, used to measure the same lid margin thickness at the central lower lid.

Results: The mean age of volunteers was 39.1 ± 13.7 years. The LLMT in 60 subjects (25 males and 35 females) measured by a vernier micrometer and AS-OCT was 1.03 ± 0.25 mm and 0.82 ± 0.21 mm, respectively. There was a significant difference between two measurements (P < 0.001). In addition, intraclass correlation coefficient (ICC) was engaged to evaluate the reliability and agreement of two measurements (ICC = 0.83). Bland-Altman plots demonstrated that 57 of 60 spots were within 95% limits of agreement. No adverse events were detected in all subjects after the measurements.

Conclusion: Although the LLMT measured by AS-OCT was less than that measured by a vernier micrometer, AS-OCT providing quantitative measurements and imaging data was also seemed to be a reliable method with a good agreement. It could be a substitute for a vernier micrometer in clinical practice in the future.