Preretinopic changes in the colour vision of juvenile diabetics

Aims-To examine the colour vision of juvenile patients suffering from diabe tes mellitus without retinopathy in relation to metabolic and ophthalmic st ate. Methods-Metameric matches, both Rayleigh (red/green) and Moreland (blue/ gr een) were used to test the colour vision yearly of 10 juvenile patients. Th e patients were monitored over 4 years, and during the final year, their bl ood glucose level was determined directly after testing colour vision. An o phthalmic examination was performed on the day of colour vision testing and blood and urine were analysed regularly throughout the 4 years. Their resu lts are compared with an aged matched control group of 20 subjects, seven o f whom were retested after 9-16 months. Results-After 4 years, the colour vision results show an enlarged matching range for the Moreland match, as well as a smaller increase in the matching range for the Rayleigh match. No significant correlation was found between blood glucose at the time of testing and any of the variables measured. Conclusion-The pattern of colour vision deficits in metameric matching show n by juvenile diabetics is consistent with post-receptoral alterations of t he inner retina, at this preretinopic stage of disease. Duration of diabete s is correlated with both colour vision changes and morphological alteratio n of the retina.