Is the lens canned?

Abstract

The ocular lens somehow remains pellucid despite bombardment by ultraviolet radiation and endogenous hydrogen peroxide (present in the humoral fluids which bathe tissue). The lens and vitresous humors contain exceptionally high concentration of reducing substances, particularlty acid, though to be important in lenticular oxidant defense. However, in the pressure of traces of transition metals, or when exposed to ultraviolet radiation, ascorbic acid readily reacts with oxygen, yeilding hydrogen peroxide, and damaging lens crystallins. We propose the alternative hypothesis that the real antioxidant function of ascorbic acid, particularly that in the aqueous and vitreous humors, may be effecting the conversion of oxygen to water. Because the lens lacks a blood supply, coupled reactions acid with oxygen in the humoral fluid spaces should produce a metabolically sustained anaerobiosis. If so, nature may have preinvented the process of cannning, wherein food (or in this case, the lens) is preserved by a combination of sterility and anoxia. © 1991.