Multifocal oscillatory potentials in type 1 diabetes without retinopathy

PURPOSE. To study multifocal recordings of oscillatory potentials (m-OPs) i n diabetic (Type 1) eyes that have no visible fundus alterations, to ascert ain whether topographical changes in sensitivity are evident when compared with recordings from control subjects. METHODS. The Visual Evoked Response Imaging System (VERIS; EDI, San Diego, CA) system was used to elicit m-OPs from 61 independent areas, subtending t he central 30 degrees of the retina, from 24 eyes of 12 patients with diabe tes without retinopathy and from 26 eyes of 14 control subjects. For each g roup of subjects, the mean first- and second-order (first slice) kernel com ponents of the responses for one eye, randomly chosen from each subject, we re analyzed and compared for a retinal ring analysis and for an analysis of retinal quadrants. RESULTS. Both first- and second-order kernel responses of the diabetic grou p show significant delays in the implicit times of some of the m-OPs, compa red with those of the control group. No significant changes in amplitude we re found. For the first-order component, significant differences are found for both potentials between 5 degrees and 22 degrees eccentricity, for the nas:ll retina, and for one of the potentials for the remaining retinal area s. In the second-order kernel responses, the differences are significant fo r two of the three potentials in the midperiphery between 5 degrees and 13 degrees eccentricity, with the central potential being significantly delaye d in all rings and quadrants. CONCLUSIONS. Patients with diabetes without retinopathy show prolonged late ncies in m-OP recordings. This indicates an alteration in inner retinal sen sitivity that can be explained by an impaired rod- cone interaction.