Determination of the average thickness of a contact lens

The amount of gas moving through a contact lens depends upon its permeability to the gas and its thickness. The lens thickness used to calculate transmissibility is often the center thickness, which is rarely the average lens thickness. A technique is presented which shows how lens mass can be used to determine the average lens thickness. This average thickness can be used to calculate the oxygen transmissibility of a contact lens of known oxygen permeability.