Oscillatory potentials, macular recovery time, and diabetic retinopathy through 3 years of intensified insulin treatment

Forty-five diabetic patients, 18 to 45 years of age, with mild or no retinopathy, were randomly assigned to continuous subcutaneous insulin infusion (CSII), multiple injections (Mls), and conventional insulin treatment (CIT). The effects of near-normoglycemia (CSII and MI) on oscillatory potentials (electroretinography ERG]) and macular recovery time (nyctometry) were studied prospectively for 41 months. Before randomization, the amplitudes of oscillatory potentials were negatively correlated to age (P = 0.002) and positively correlated to the diameter of retinal veins (P less than 0.05). Men had shorter macular recovery time than women (P = 0.03). Nyctometry and oscillatory potentials were not related to mean blood glucose values, glycosylated hemoglobin (HbA1), retinopathy, blood pressure levels, or duration of diabetes. Changes in metabolic control (MI and CSII; P less than 0.01) and in microaneurysms and hemorrhages (CSII and CIT) during the study did not affect oscillatory potentials or nyctometry. Soft exudates (15 patients) and proliferative retinopathy (1 patient) transiently developed with MI and CSII regimens. No changes in oscillatory potentials or nyctometry were observed and no pretreatment characteristics of these parameters predicted the occurrence of these ischemic lesions. At the stage of proliferation, however, lowered amplitudes of oscillatory potentials and lengthened macular recovery time were observed.