The cornea swells in the posterior direction under hydrogel contact lenses

Two mathematical models were developed to describe the topographical cornea l swelling response to hydrogel contact lenses and the effect of these chan ges on refractive error. In one, corneal thickness changes resulted in defo rmation of the anterior corneal surface. In the other, the posterior surfac e only was deformed. Refractive error, corneal thickness and corneal shape were monitored in a sample of adapted contact lens wearers with one eye pat ched for 4 h while wearing a soft contact lens. The experimental data were most consistent with the model in which the posterior surface only was defo rmed. (C) 1999 The College of Optometrists. Published by Elsevier Science L td. All rights reserved.