Variations in the central corneal thickness during the menstrual cycle in Indian women

PURPOSE: To determine the changes in central corneal thickness (CCT) during the menstrual cycle in Indian women. METHODS: A prospective observational clinical study at a tertiary care center between December 2015 and December 2018. One hundred and twenty sixty women between 18 and 45 years were included. The CCT was measured using an ultrasound pachymeter at three specific timelines of the menstrual cycle: at the beginning (1(st) to 3(rd) day), during ovulation time (14(th) to 16(th) day), and at the end of the cycle (28(th) to 33(rd) day). Phases of the cycle were confirmed by the urine luteinizing hormone level. RESULTS: The mean CCT of both eyes was 541.76 ± 4.21 μm, 559.21 ± 4.50 μm, and 544.52 ± 8.06 μm at the beginning, mid, and end of cycle, respectively. The mean CCT of the right eye was 541.68 ± 4.15 μm, 559.08 ± 4.50 μm, and 544.44 ± 8.06 μm and of the left eye was 541.84 ± 4.27 μm, 559.35 ± 4.50 μm, and 544.61 ± 8.06 μm at the beginning, mid, and end of cycle, respectively. CONCLUSION: The CCT value was significantly (P < 0.001) higher during ovulation compared to the beginning and end of the menstrual cycle. Our study recommends adding menstrual history in the workup of women undergoing refractive surgery as physiological variations in the CCT may result in unexpected surgical outcomes.