CORNEAL THICKNESS IN DAILY CONTACT LENS WEAR

Abstract

The corneal responses to daily wear of Scanlens 75 high water content lenses, average center thickness 0.23 mm, and of Bausch and Lomb Soflens U3 low water content lenses, center thickness 0.07 mm, were compared. Calculations of oxygen transmissibility indicated that corneal swelling might be less for the former lenses than for the latter lenses. This assumption was proved to be correct. The average increase in corneal center thickness over the day (14 h) during a 4 wk period was 1.6% for Scanlens 75 and 2.8% for Soflens U3. This difference was statistically highly significant (P < 0.001). The thickness increase was greatest during the 1st week. Tests with thicker lenses showed that the thicker the lenses are, the more important it is to choose high water content lenses. The closed eye period increased corneal swelling in extended lens wear. The results favor a program based on certain high water content lenses and a daily wear schedule.