IGF1 and diabetic retinopathy: There are a number of growth factors which have been associated with the development of diabetic retinopathy and these include basic fibroblast growth factor (bFGF) [119], insulin-like growth factor-1 (IGF-1) [120, 121], angiopoietin-1 and -2 [122–124], stromal-derived factor-1 [125], epidermal growth factor (EGF) [126], transforming growth factor-beta 2 (TGF-β2) [127], platelet-derived growth factors (PDGFs) [128], and erythropoietin [129].