Causes are divided into embolic, hemodynamic, ocular, neurologic, and idiopathic 
Carotid emboli or Cardiac emboli in origin causing
Central Retinal Artery Occlusion (CRAO)
Central Retinal Vein Occlusion (CRVO)
Drug abuse-related intravascular emboli
Central Retinal Artery Occlusion (CRAO)
Central Retinal Vein Occlusion (CRVO)
Carotid stenosis
Arteritis (Temporal arteritis, Takayasu arteritis)
Hypoperfusion (CHF, Hyperviscosity syndrome, hypercoagulable state)
Ischemic optic neuropathy
Central Retinal Artery Occlusion (CRAO)
Central Retinal Vein Occlusion (CRVO)
Nonvascular causes
Retinal Detachment
Vitreous hemorrhage
Malignancy
Central Retinal Artery Occlusion (CRAO)
Central Retinal Vein Occlusion (CRVO)
Retinal Detachment
Vitreous hemorrhage
Malignancy
Migraine
Papilledema
Optic neuritis
Intracranial mass
Intracranial hemorrhage
Multiple Sclerosis
Psychogenic
Diagnosis of exclusion
Painful
Arteritic anterior ischemic optic neuropathy
Optic neuritis
Temporal arteritis†
Painless<unk> 
Central retinal artery occlusion (CRAO)†
Central retinal vein occlusion (CRVO)†
High altitude retinopathy
Open-angle glaucoma
Posterior reversible encephalopathy syndrome (PRES)
Retinal detachment†
Stroke†
Vitreous hemorrhage
Traumatic optic neuropathy (although may have pain from the trauma)
Arteritic anterior ischemic optic neuropathy
Optic neuritis
Temporal arteritis†<unk> 
Central retinal artery occlusion (CRAO)†
Central retinal vein occlusion (CRVO)†
High altitude retinopathy
Open-angle glaucoma
Posterior reversible encephalopathy syndrome (PRES)
Retinal detachment†
Stroke†
Vitreous hemorrhage
Traumatic optic neuropathy (although may have pain from the trauma)
†Emergent Diagnosis
Amaurosis fugax
Causes are divided into embolic, hemodynamic, ocular, neurologic, and idiopathic [3]
Pellagra
Carotid emboli or Cardiac emboli in origin causing
Traumatic mydriasis
Central Retinal Artery Occlusion 
Proctalgia fugax
Central Retinal Vein Occlusion 