Sensory Adaptation to Silicone Hydrogel Contact Lens Wear Is Not Associated With Alterations in the Corneal Subbasal Nerve Plexus.

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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. 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, χ, and Wilcoxon signed-rank tests were used for statistical analyses. 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 μm/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. Sensory adaptation to CL wear is not mediated through attenuation of the subbasal nerve or reduction of corneal tactile sensitivity in CL-naive users.