All of the following may be used to differentiate Central Retinal Venous Occlusion (CRVO) from ocular Ischemic syndrome due to carotid artery stenosis, Except –

Dilated retinal vein is seen both in CRVO and ocular ischemic syndrome; therefore, this feature cannot differentiate these two. However, in CRVO vein is tortuous while in ocular ischemic syndrome it is non-tortuous. Retinal artery perfusion pressure is decreased in ocular ischemic syndrome and is normal in CRVO. Ophthalmodynamometry shows low ophthalmic artery pressure in ocular ischemic syndrome and normal to high pressure in CRVO.