Visual fields at different stages of diabetic retinopathy

Available studies on visual field disturbances in diabetic retinopathy have shown conflicting results, obtained with different and often non-comparable techniques. We have studied visual fields at different stages of diabetic retinopathy with modern sensitive computerized technique taking precautions to limit disturbing effects of random field variation and lack of perimetric experience. Sixty-three diabetic patients, insulin-dependent and non-insulin dependent, were each subject to three test sessions using the 30-2 full threshold program of the Humphrey perimeter. Retinopathy levels ranged from 10 to 65 in the ETDRS Final scale. In eyes without retinopathy or with very mild and mild disease (levels 10-35) mean deviation values exceeding the p < 5% level occurred in only 4% of eyes in trained sessions, and the number of test points with significantly reduced sensitivity did not exceed that expected in normal eyes. In moderate and moderately severe diabetic retinopathy (level 43-47) and in severe non-proliferative and proliferative retinopathy (levels 53-65) there was clear evidence of field loss, however, with significantly reduced mean deviation values in 44% of the eyes and 6.5% of tested points showing reproducible loss of sensitivity. Thus, there was no evidence of field loss in eyes with mild disease, but clear field defects in eyes with more advanced disease. Significantly reduced sensitivity was often correlated with retinal non-perfusion and there was seen a tendency towards more correlation in the midperiphery than paracentrally.