CORNEA, vol.38, no.9, pp.1142-1146, 2019 (SCI-Expanded)
Purpose: To evaluate corneal subbasal nerve alterations in contact lens (CL)-naive silicone hydrogel CL wearers and to investigate the relationship between structural subbasal nerve changes with corneal sensitivity. Methods: Twenty eyes of 20 neophyte daily silicone hydrogel CL wearers and 20 eyes of age-matched control subjects were recruited for this prospective longitudinal study. Corneal subbasal nerve densities were evaluated using in vivo confocal microscopy. Central corneal tactile sensitivity was measured using Cochet-Bonnet esthesiometers. In vivo confocal microscopy and Cochet-Bonnet esthesiometry were performed before and at the 6-month time point after the initiation of CL wear. Two-way repeated measures analysis of variance, chi(2), and Wilcoxon signed-rank tests were used for statistical analyses. Results: The mean ages of CL users and control subjects were 21.8 +/- 1.8 years (range = 19-24 years) and 21.5 +/- 2.3 years (range = 20-24 years), respectively (P = 0.579). Compared with their baseline values, there were no significant changes at the 6-month follow-up period in the mean total subbasal nerve fiber length (2266.6 +/- 414.6 vs. 2277.9 +/- 405.0 mu m/frame; P = 0.432), mean total subbasal nerve branch density (10.4 +/- 1.5 vs. 10.5 +/- 1.3 nerves/frame; P = 0.655), or the mean long nerve fiber density (4.7 +/- 0.7 vs. 4.8 +/- 0.7 nerves/frame; P = 0.564) of CL users. Mechanical corneal sensitivity remained unaltered during the 6-month period in CL users (11.2 +/- 0.5 vs. 11.2 +/- 0.5; P = 1.000). No significant changes were observed in the subbasal nerve plexus or corneal tactile sensitivity of the control subjects during the study interval. Conclusions: Sensory adaptation to CL wear is not mediated through attenuation of the subbasal nerve or reduction of corneal tactile sensitivity in CL-naive users.