Permeability of the Cornea and the Blood-Aqueous Barrier to Oxygen

Abstract

INTEREST in the permeability of the cornea to oxygen arose out of recent investi- gations on corneal metabolism and the influence of metabolism on the hydration of the tissue. Langham (1952) reported that the concentration of lactic acid in the cornea varied inversely with the oxygen tension in the tear film and concluded that oxygen obtained directly from the atmosphere was utilized by the cornea, and that the oxygen entering from the bloodstream and the aqueous humour was unlikely to meet the requirements of the whole cornea. In studies of a rather different nature, Consequently, to confirm whether or not the respiratory requirements of the tissue could be met by the diffusion of oxygen from the aqueous humour, direct measures of the oxygen tension in the aqueous humour and the rate of diffusion of oxygen across the cornea have been made. At the same time, the opportunity has been taken of assessing by an independent means the conclusion of Fischer (1930) that the cornea shows a unidirectional permeability to oxygen in the inward direction.