Corneal Edema With Hydrogel Lenses and Eye Closure

Subjects wore hydrogel lenses of two different thicknesses (0.07 mm and 0.18 mm) on one eye and no lens on the other eye during 3‐hour periods of eye closure. They developed more corneal edema (12.7%) with the thicker lenses than with the thinner lenses (7.9%) and more corneal edema with the thinner lenses than with no lens (0.9%). The results suggest that hydrogel lens thickness would have to be less than 20 nm to reduce corneal edema to levels that develop when the eyes are closed without a contact lens.