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 (μm/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 μm/wk, respectively (P =.99). There was no difference in corneal nerve migration rate between male (41.1 ± 13.5 μm/wk) and female (43.7 ± 13.2 μm/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.