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

•We examined the corneas of 10 participants who wore hydrogel contact lenses.•We evaluated changes in central corneal Langerhans cell density over 8 h.•Langerhans cells increased 2X after 2 h, indicating sub-clinical inflammation.

PurposeTo determine the impact of contact lens wear on Langerhans cell density (LCD) in the central cornea over an 8 h period.MethodsTen 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.ResultsAt baseline, LCD was 18 ± 19 and 20 ± 19 cells/mm2 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/mm2 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.ConclusionsLCD increases two-fold within the first 2 h of lens wear, indicating a rapid, sub-clinical inflammatory response to uncomplicated lens wear.