Central retinal vein occlusion (CRVO) A, Diffuse retinal hemorrhage following CRVO. The damaged retina will be replaced by gliosis. B, Histology of long-standing CRVO shows loss of the normal lamellar architecture of the retina, marked edema with cystic spaces (asterisk) containing blood and proteinaceous exudate, vitreous hemorrhage, and nodular hyperplasia of the RPE (arrow) (H&E stain).