Glucose concentration in the vitreous of nondiabetic and diabetic human eyes.

Glycation (nonenzymatic glucosylation) of collagen may play a role in the primary pathology of the vitreous in diabetes. The extent of glycation is determined by the glucose concentration in the tissue. In this study glucose concentration was assayed in blood and vitreous samples obtained from three patient groups undergoing vitrectomy: nondiabetic patients (ND), diabetic patients with insulin-dependent diabetes mellitus (IDDM) and diabetic patients with non-insulin-dependent diabetes mellitus (NIDDM). In the ND group the glucose concentration in the vitreous (3.5 +/- 1.8 mM/l) was always lower than in the blood (9.1 +/- 3.5 mM/l). In the diabetic groups the vitreous glucose concentration was, with a few exceptions, generally lower than the blood glucose concentration. The vitreous glucose concentration in these groups was generally higher (IDDM 9.4 +/- 3.3 mM/l, NIDDM 7.2 +/- 3.9 mM/l) than in the ND group, and in 15 specimens exceeded 11 mM/l, a level increasing the probability of collagen glycation in the vitreous of diabetic patients.