VEGFA and Cerebral ischemia: Compared with the DM group, the DM+cerebral ischemia group had significantly increased expression of VEGF in the retinal tissue of tree shrews (P < 0.01), suggesting that cerebral ischemia can enhance the expression of VEGF in diabetic tree shrew, while in the DM+cerebral ischemia+ischemic PC group, the thickness of the retina layers was close to that of normal retina and the morphology of pigmented cells was normal.