Responses to oxygen deprivation: variations among human corneas.

The cornea's interface with the atmosphere makes it uniquely accessible among avascular tissue for the study of local oxygen demand and proximal reservoir dynamics. Corneal oxygen-uptake rates obtained under normoxic vs hypoxic conditions are not predictive of each other. Proximal tissue reservoirs appear to play a role in moderating oxygen demands following periods of hypoxic stress: as the ratio of epithelia/stromal thickness rises, so does oxygen demand (r = +0.932, P = 0.01). The thickness of the stroma was most closely related to the oxygen uptake rates associated with the normal, open eye (r = +0.773, P = 0.07), whereas the thickness of the epithelium was more closely related to rates obtained after the cornea had been deprived of oxygen (r = +0.783, P = 0.07).