http://www.ncbi.nlm.nih.gov/pubmed/22695936
Supplementation with antioxidants attenuates transient worsening of retinopathy in diabetes caused by acute intensive insulin therapy.
Ascorbic acid, α-lipoic acid, and α-tocopherol also decreased superoxide anion production
Insulin can increase ROS production through an NAD(P)H, phosphatidylinositol 3´-kinase-dependent mechanism in bovine retinal microvascular endothelial cells ex vivo. ROS can regulate insulin-induced VEGF expression. Supplementation with antioxidants may help to attenuate the transient worsening of retinopathy in diabetes caused by acute intensive insulin therapy.