Last reviewed 06/2023

  • external compression due to hypertensive or sclerotic changes in the central retinal artery in the optic nerve head
  • occlusion of the central retinal vein at its exit from the eye by raised intraocular pressure e.g. chronic glaucoma
  • venous stasis - increased viscosity e.g. dysproteinaemias, obstructive pulmonary disease; reduced blood pressure e.g. trauma, carotid artery occlusive disease, treatment for hypertension; reduced perfusion pressure from vasospasm of the central retinal artery