Stability of CAB contact lenses with hydration

The effects of hydration on the base curve of CAB lenses were measured with a radiuscope. A significant amount of lens warpage and variability in curvature was detected in all lenses under conditions of continuous hydration. Thinner lenses flattened more than thicker lenses of the same power. Lenses of greater minus power flattened more than lenses of less minus power for a given lens thickenss. Plus power lenses were more stable than minus power lenses. Control lenses, stored dry, did not flatten or warp.