AbstractThe only practical means of making a clinical measurement of oxygen flux into a cornea under a contact lens is by pressing a Clark-type oxygen sensor to the anterior surface of the lens. The earlier limitation to lenses of low water content has been removed and a general method suitable for soft lenses of all transmissibility is presented here. The procedure allows an estimate of oxygen tension under the lens and oxygen flux into the cornea. The method requires a minimum amount of calculation and does not require a prior calibration on the contact lens wearer, but instead gives a direct, absolute measurement of oxygen tension and flux.