The supply of nutrient metabolites to the cornea is largely dependent on the levels of aqueous humour metabolites. When the ciliary body was destroyed totally by cyclodiathermy, a deficiency of glucose was observed in the aqueous humor and consequently in the corneal stroma. The diminished glucose levels could be increased by intravenous glucose infusions to values above normal. On the other hand, fructose infusions may be of value as nutrient metabolites of the cornea. Analyses of the fructose levels in the anterior segment of the eye showed that significant quantities of fructose were present in the corneal epithelium with a concentration gradient to the stroma and the aqueous humor. When the corneal epithelium was removed, the fructose of the corneal stroma and the aqueous humor was significantly diminished. In aphakic eyes without corneal epithelium, the fructose levels were decreased to nearly zero values both in the corneal stroma and in the aqueous humor. It was concluded that corneal epithelium was able to synthesize fructose and release it into the aqueous humor.