Development of brightness matching and colour vision deficits in juvenile diabetics

We studied hue discrimination and brightness matching throughout the spectr um in ten juvenile patients suffering from diabetes mellitus (Type I) with no (eight patients) or mild (two patients) retinopathy. In addition, the FM 100-Hue test was performed. The data were collected once every year over 5 years. Over the 5 years, the diabetics show a continual change in the shap e of their brightness matching function. Wavelength discrimination ability remains quite stable with time at the long end of the spectrum but is varia ble at short wavelengths. FM-100 error scores remain similar over the perio d tested, at a level slightly higher than that of a control group. Addition al experiments show that the sensitivity of the S-cone in the diabetic grou p is similar to that of controls. The results can be explained by an early relative reduction in the sensitivity of post-receptoral processes in juven ile diabetics. (C) 1999 Elsevier Science Ltd. All rights reserved.