A 56 year old woman came to the emergency room 3 hours after visual loss in the right eye. Visual sensitivity limits to light perception in the right eye. Examination reveals pupillary defect whereas anterior surface of both eye are normal. Fundus examination shows a red lesion with pale retina. Probable diagnosis
Central vein occlusion Proliferative diabetic retinopathy Background diabetic retinopathy Central retinal artery occlusion