Using human retinal endothelial cells (HRECs) in culture and the rat model of diabetic retinopathy, we have investigated the effect of hyperglycemia on Drp1-Fis1 interactions and mitochondrial transport of Drp1, and the results are confirmed in retinal microvessels from human donors with diabetic retinopathy. Here, FIS1 is linked to diabetic retinopathy.