Fig. 1

Featured microvascular alterations of eye signs: ischaemic area (more than 3 capillary grid areas without vessels under a 40× microscope); reticulum deformity (the capillaries increase, the mesh decreases, and the dendrites become grid-like); microangioma (can be divided into local round, fusiform, cystic dilation, or isolated and scattered around the vessel); and wound spot (vascular blind end-shaped brown, purple, or dark blue material deposition). Bleeding is exudative (fuzzy vessel wall), and there are ruptures (wound spots, patches) around capillaries