ABSTRACT The refraction of the eye may change after wearing contact lenses: these changes are often attributed only to changes in the anterior corneal curvature. However, refractive changes may also be the result of variations in the posterior corneal curvature, corneal thickness and index of refraction as well as a change in the depth of the anterior chamber. The differential calculus permits derivation of equations describing these changes and the results confirmed by computer modification of the basic equation.
Rengstorff et al. (1971) studied this question.