Acute visual loss demands urgent NP evaluation to identify treatable emergencies. Central retinal artery occlusion (CRAO) presents as sudden, painless, monocular vision loss with a pale retina and cherry-red spot at the macula (the fovea appears red because the underlying choroidal blood supply is visible through the thin foveal tissue while surrounding ischemic retina is pale); CRAO is an ophthalmic stroke equivalent requiring evaluation for embolic source (carotid disease, atrial fibrillation, valvular disease). Central retinal vein occlusion (CRVO) shows diffuse retinal hemorrhages in all four quadrants (blood and thunder fundus), dilated tortuous veins, and disc edema. Giant cell arteritis (GCA/temporal arteritis) causes vision loss in patients over 50 with headache, jaw claudication, scalp tenderness, and elevated ESR (greater than 50 mm/hr) and CRP; the clinician initiates high-dose prednisone (1 mg/kg/day) immediately upon clinical suspicion BEFORE biopsy results (temporal artery biopsy within 2 weeks). Acute angle-closure glaucoma presents with severe eye pain, mid-dilated fixed pupil, hazy cornea, and intraocular pressure greater than 40 mmHg -- treat with timolol, pilocarpine, and IV acetazolamide while arranging emergent ophthalmology consultation for iridotomy. Retinal detachment...