Overnight corneal swelling response in adapted and unadapted extended wear patients.

This investigation compared the overnight swelling response in adapted and unadapted subjects who were wearing a 0.035 mm, low water content hydrogel contact lens. Six subjects who had not worn contact lenses previously (unadapted) and six subjects who had worn extended wear hydrogel lenses for 1.5 years participated in the study. Baseline corneal thickness measurements were taken in the evening and after 7.5 h of sleeping with the lenses on overnight. The unadapted subjects showed more overnight swelling and at each time interval for 3 h the next morning under open-eye conditions. The rate of deswelling was the same for each group.