Low glycation level and browning in human cataracts.

The extent of human cataract glycation has been determined by the 5-HMF/TBA method in 236 samples (53 from diabetic patients and 183 from non-diabetic controls). The brownish-yellow coloration typical of the advanced products of the Maillard reaction was measured spectrophotometrically. Glycation of crystallins was three times higher in diabetics than in controls, and was positively correlated with age in the latter group. The two groups did not differ significantly as regards the degree of browning, which was also uncorrelated with the primary products measured by the 5-HMF/TBA method. It is concluded that lens glycation is relatively mild and does not determine the intensity of the characteristic brownish-yellow colour of diabetic and senile cataracts. It is suggested that other coloured compounds produced with age interfere at the relevant wavelengths.