It is helpful to have shells of uniform thickness to study gas permeability of contact lenses. A formula is derived and evaluated for the back vertex power of concentrically surfaced lenses of various base curves, thicknesses, and indexes of refraction.Key Words: gas permeability, contact lenses, back vertex power, concentrically surfaced lenses
Received June 16, 1981; revision received September 23, 1981.
* Optometrist, Ph.D., Member of Faculty.
Barry A. Weissman
Jules Stein Eye Institute
UCLA School of Medicine
Los Angeles, California 90024
© 1982 American Academy of Optometry