The story is short because the physiology is: "The vision in my right eye just went out — like a shade dropped." No pain, no trauma, one eye, minutes ago. In too many systems that patient is routed to an eye clinic with an appointment measured in days. The retina, meanwhile, is doing what any brain tissue does without an artery — dying by the minute.

Central retinal artery occlusion is a stroke that happens to be visible with an ophthalmoscope. The 2021 AHA scientific statement says the operational part plainly: CRAO patients should be triaged emergently, like stroke, to centers that can evaluate and treat stroke.1

Recognition and the two-item differential that cannot wait

The classic exam: profound monocular acuity loss (often counting-fingers or worse), a relative afferent pupillary defect, and on fundoscopy a pale, edematous retina with a cherry-red spot at the macula — the choroid's color showing through the one spot of thin retina. An embolus (Hollenhorst plaque) is sometimes visible sitting in the arterial tree, naming its own source. A minority of patients have a cilioretinal artery sparing central vision — better acuity, same disease.

Two look-alikes change management immediately. Giant cell arteritis: in any patient over 50, ask about headache, jaw claudication, scalp tenderness, polymyalgia symptoms, and send ESR/CRP — arteritic central retinal or ophthalmic artery occlusion gets corticosteroids now to save the other eye, and no antithrombotic strategy substitutes.1 And amaurosis fugax — the same territory's TIA: transient monocular gray-out, sight restored. It shares the entire urgency and workup of CRAO (it is the warning shot; we cover the "it went away" trap in what is a TIA) without the deficit — the best version of this disease to catch.

Sudden painless one-eye vision loss has two emergencies inside it: the retinal stroke, and — over 50 — the arteritis that wants the other eye next.

Acute treatment: honest about the evidence, fast anyway

Natural history is grim — meaningful spontaneous visual recovery is the exception. The traditional "conservative" maneuvers (ocular massage, anterior chamber paracentesis, IOP-lowering drops, hemodilution) have never shown convincing benefit and should not consume the clock.1 The live question is thrombolysis. A patient-level meta-analysis of observational series found IV fibrinolysis within 4.5 hours associated with visual recovery in roughly half of treated patients versus under a fifth with natural history — a signal, not a verdict, given the non-randomized substrate.2 The AHA statement lands where honest evidence lands: early IV alteplase within 4.5 hours may be considered in appropriately selected patients without contraindications, individualized, ideally within trials — and several randomized trials are underway.1 Eligibility logic borrows the standard lytic checklist; what cannot be borrowed is time, which is why the 911-not-clinic reflex is the whole ballgame.

After the eye: the workup the patient is owed

A retinal infarct carries the same message as a hemispheric one: somewhere upstream, a source. The evaluation is the standard stroke workup with one emphasis — the ipsilateral carotid first, because the eye is the carotid's first intracranial customer via the ophthalmic artery, and symptomatic high-grade stenosis found here is revascularization-eligible disease. Then echocardiography and rhythm monitoring for the cardioembolic sources, MRI of the brain (a meaningful fraction of CRAO patients harbor concurrent silent cerebral infarcts — another argument for stroke-unit disposition), and risk-factor treatment to secondary-prevention standard.13 Antithrombotic selection afterward follows mechanism, exactly as for any ischemic stroke (the framework).

And say the quiet part to the patient: the fellow eye and the brain are now the things being protected. Vision rehabilitation referral, driving assessment where field loss matters, and honest prognosis counseling round out care that too often ends at the diagnosis.

The bottom line

Wire the reflex into triage: sudden painless monocular vision loss = code stroke, plus an ESR question when the patient is over 50. Skip the massage-and-drops theater, have the honest early-thrombolysis conversation inside 4.5 hours where appropriate, and give every CRAO the carotid-first stroke workup and the secondary prevention its mechanism demands. The eye is the one piece of the CNS you can watch infarct in real time — the point is to stop watching and run the pathway.