Changes in corneal Langerhans cell density during the first few hours of contact lens wear

Purpose: To determine the impact of contact lens wear on Langerhans cell density (LCD) in the central cornea over an 8 h period. Methods: Ten participants wore a hydrogel lens in one eye (the experimental eye) for 8 h. The contralateral non-lens-wearing eye served as a control. The central cornea of each eye was examined at the level of the subbasal nerve plexus using a laser scanning corneal confocal microscope, at baseline (prior to lens wear), then every 2 h for 8 h. Results: At baseline, LCD was 18 +/- 19 and 20 +/- 19 cells/mm(2) in the experimental and control eyes, respectively. In the experimental eye, LCD increased to 36 +/- 32 cells/mm2 after 2 h and then decreased gradually to 30 +/- 31 cells/mm(2) after 6 h. LCD was greater in the experimental eye than the control eye at the 2, 4, 6 and 8 h time points (p < 0.05). LCD remained constant in the control eye throughout the 8 h experiment. Conclusions: LCD increases two-fold within the first 2 h of lens wear, indicating a rapid, sub-clinical inflammatory response to uncomplicated lens wear. (C) 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.