Painful
Arteritic anterior ischemic optic neuropathy
Optic neuritis
Temporal arteritis†
Painless
Amaurosis fugax
Central retinal artery occlusion (CRAO)†
Central retinal vein occlusion (CRVO)†<unk> 
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†
Amaurosis fugax
Central retinal artery occlusion (CRAO)†
Central retinal vein occlusion (CRVO)†<unk> 
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
Acute mountain sickness
Chronic mountain sickness<unk><unk>  cerebral edema<unk><unk>  pulmonary edema<unk><unk>  peripheral edema<unk> <unk><unk>  pharyngitis and bronchitis
Ultraviolet keratitis
High altitude retinopathy
Painful
Open-angle glaucoma
Arteritic anterior ischemic optic neuropathy
Traumatic optic neuropathy
Optic neuritis
Central retinal artery occlusion
Temporal arteritis†