Corneal Nerve Migration Rate in a Healthy Control Population

PURPOSE: The purpose of this study was to establish an age-dependent normative range and factors affecting the migration rate of the corneal subbasal nerve plexus in a healthy control population. METHODS: Corneal nerve migration rate was measured in 60 healthy participants grouped by age: A, aged 20 to 39 years (n = 20); B, 40 to 59 years (n = 20); and C, 60 to 79 years (n = 20). Laser-scanning corneal confocal microscopy was performed on the right eye of all participants at baseline and again after 3 weeks. Fully automated software was used to montage the frames. Distinctive nerve landmarks were manually reidentified between the two montages, and a software program was developed to measure the migration of these landmark points to determine corneal nerve migration rate in micrometers per week (mu m/wk). RESULTS: The mean +/- SD age of all participants in the study was 47.5 +/- 15.5 years; 62% of participants were male. The average corneal nerve migration rates of groups A, B, and C were 42.0 +/- 14.0, 42.3 +/- 15.5, and 42.0 +/- 10.8 mu m/wk, respectively (P = .99). There was no difference in corneal nerve migration rate between male (41.1 +/- 13.5 mu m/wk) and female (43.7 +/- 13.2 mu m/wk) participants (P = .47). There was no significant correlation between age (P = .97), smoking (P = .46), alcohol use (P = .61), and body mass index (P = .49, respectively) with corneal nerve migration rate. However, exercise frequency correlated significantly (P = .04) with corneal nerve migration rate. CONCLUSIONS: Corneal nerve migration rate varies in healthy individuals and is not affected by age, sex, or body mass index but is related to physical activity.