In non-proliferative retinopathy, this permeability causes macular edema which, over time, leads to capillary widening and degeneration of the retina whereas in proliferative retinopathy, there is excessive formation of blood vessels (vascularisation) around the optic disk; this aberrant neovascularisation is a major contributor to vision loss and has been attributed to hyperglycaemia-induced increase in local vitreous vascular endothelial growth factor (VEGF) levels in patients with diabetes [5–8]. The gene discussed is VEGFA; the disease is retinal disorder.