OBJECTIVE To assess light sensitivity and morphologic changes of capillary nonperfused areas in diabetic retinopathy. METHODS Prospective, observational cross-sectional study. METHODS Seventeen consecutive patients (20 eyes) with areas of capillary nonperfusion resulting from severe nonproliferative or proliferative diabetic retinopathy were included in the study. All eyes underwent fluorescent angiography and fundus-related microperimetry. Nonperfused areas of the retina were scanned with optical coherence tomography (OCT). RESULTS In all 20 diabetic eyes, areas of capillary nonperfusion detected by fluorescein angiography were associated with the loss of retinal sensitivity. At the edges of the nonperfused area, retinal sensitivity tended to be reduced. The OCT images suggested a structural disturbance of the inner retina and high-reflectivity deposition located between the outer segments of photoreceptor and the retinal pigment epithelium corresponding to the areas of capillary nonperfusion. CONCLUSIONS Areas of capillary nonperfusion resulting from severe nonproliferative or proliferative diabetic retinopathy show morphologic changes of the retinal structure, which may lead to a loss of sensitivity.