Measurement of the Lower Lid Margin Thickness by Anterior Segment Optical Coherence Tomography

Purpose: To verify the feasibility of using anterior segment optical coherence tomography (AS-OCT) to measure the lower lid margin thickness (LLMT) from posterior lash line to the mucocutaneous junction. Methods: This was a prospective, single-center, observational study. Fifty-six volunteers between 20 and 79 years old with normal healthy eyes were included in this study. Using AS-OCT to measure the LLMT at the middle position was separately performed by two operators under the same conditions. Results: The mean age of 56 subjects (24 males and 32 females) was 45.4 +/- 15.7 years. The LLMT measured by AS-OCT between two operators was 0.86 +/- 0.23 mm and 0.85 +/- 0.22 mm, respectively. The reliability and repeatability between two operators were evaluated by intraclass correlation coefficient (ICC = 0.97). Based on one operator's measurements, the LLMT was 0.70 +/- 0.10 mm at ages 20-29, 0.68 +/- 0.09 mm at ages 30-39, 0.94 +/- 0.12 mm at ages 40-49, 0.93 +/- 0.20 mm at ages 50-59, 1.03 +/- 0.15 mm at ages 60-69, and 1.24 +/- 0.19 mm at ages 70-79, which indicated a significant positive correlation with age (r(s) = 0.74, p < 0.001). In addition, there was a significant difference in the LLMT between genders (0.94 +/- 0.26 vs. 0.80 +/- 0.19 mm, p = 0.03). Conclusions: A good agreement between two operators indicated that it seemed to be feasible to use AS-OCT to measure the LLMT. Additionally, we found that the LLMT appeared to be closely related to age and gender.