Alteration of tear cytokine balance by eye closure: analysis by multicytokine assay

To study the effects of eye closure on the balance of tear cytokines.A total of 17 healthy volunteers with normal eyes were recruited. Tears (10 microl) were collected by capillary outflow at 09:00. The right eyes were closed with cotton bandages for 3 h, then tears were collected from each eye separately. The concentrations of inflammatory cytokines, interleukin (IL)-1beta, IL-6, IL-8, IL-10, IL-12p70, and tumor necrosis factor (TNF)-alpha were measured by cytometric bead array.Although the concentration of each cytokine varied between eyes, the increasing ratio for 3 h showed a similar pattern in each cytokine. IL-1beta, IL-6, IL-10, IL-12p70, and TNF-alpha increased and IL-8 decreased in normal eyes. After eye closure, the increase of IL-10 significantly diminished (P=0.037); however, the other cytokines were not affected.Eye closure decreased the concentration of IL-10 in tears, which might cause a potentially pro-inflammatory status of the ocular surface.