['To establish the temporal sequence of limbal hyperaemia in humans without contact-lens wear and during conventional and highly oxygen-permeable soft-contact-lens wear.', 'Two, 16-h, non-dispensing clinical studies were conducted, each incorporating 8 h of open eye with normal blinking, followed by 8 h of eye closure during sleep. In the first study, six non-habitual contact-lens wearers did not wear contact lenses. In the second study, the same subjects were each randomly assigned, in a double-masked fashion, to wear a conventional, thin, 38% water, pHEMA soft contact lens (SCL) in one eye and an experimental high Dk (EHD), 20%-water soft contact lens in the other. Limbal redness (LR) was graded, using a 0-4 scale with decimalised subdivisions, at baseline and after 4, 8 and 16 h. ANOVA was applied to the data, and the level for statistical significance was set at p < or = 0.005.', 'In the non-wearing eye, LR changes averaged 0.2 +/- 0.2 and 0.4 +/- 0.2 grades at 4 and 16 h, respectively (inferior quadrant). The corresponding values for SCL wear were 1.0 +/- 0.6 and 1.1 +/- 0.6, while for EHD wear they were 0.2 +/- 0.4 and 0.5 +/- 0.5. Both for the normal eye and those wearing EHD lenses, increases in LR were significant only during eye closure (p < 0.005). During SCL wear, significant and larger LR increases were seen after 4 h open eye wear (p < 0.005), with only relatively small further changes being observed over the next 12 h.'] Do high-oxygen-transmissibility soft contact lenses induce limbal hyperaemia?