HIF1A and retinal ischemia: Thereby, it was speculated that the expressions of HIF-1α mRNA and miR-210 were increased in patients with CRVO combined with macular edema due to retinal ischemia and hypoxia, and miR-210 could affect the sensitivity of VEGF23, so that its expression was increased, thus damaging the blood-retinal barrier, increasing vascular permeability and further causing the aggravation of macular edema.