Oxygen flux into the human cornea when covered by a soft contact lens.

Corneal thickness was measured in human subjects who wore gel lenses that varied only in center thickness. The amount of corneal swelling that developed was a function of center lens thickness. Based on these data and the results of a previous study, the minimum oxygen tension under the lens necessary to maintain normal corneal hydration was determined to be 10 mm Hg. The critical oxygen flux into the cornea at this oxygen tension is 2 microliter/cm2 x hr. Gel-lens center thickness and oxygen permeability can be altered to increase the oxygen tension at the tear/lens interface and resultant oxygen flux into the cornea by increasing the oxygen transmissibility of the lens.