Retinal Artery & Vein Occlusions
Comprehensive emergency evaluation and protocolized management of acute retinal vascular occlusions: Central Retinal Artery Occlusion (CRAO/'ocular stroke'; sudden, painless, severe monocular vision loss, pale ischemic retina with pathognomonic foveal 'cherry-red spot', boxcarring of retinal blood columns, carotid atheroembolism vs. cardiogenic embolism vs. Giant Cell Arteritis, emergent stroke code activation, IOP reduction maneuvers); and Central Retinal Vein Occlusion (CRVO; venous thrombus at lamina cribrosa, 'blood and thunder' fundus with diffuse flame hemorrhages and macular edema).
Resuscitation Quick Actions • First 2 Minutes
CRAO is an Ocular Stroke
Activate Code Stroke/notify neurology; workup mirrors acute ischemic stroke (carotid ultrasound, echocardiogram, telemetry)
Cherry-Red Spot (CRAO)
Pale, milky, ischemic edematous retina + prominent bright 'cherry-red spot' in fovea + segmentation/boxcarring of arterioles
Giant Cell Arteritis (GCA)
Age > 50 with CRAO: check STAT ESR and CRP; if elevated, give Methylprednisolone 1g IV daily stat to save the contralateral eye!
Emergent CRAO Maneuvers
Digital ocular massage (cycles of 10s pressure/5s release), Timolol 0.5% drops, Acetazolamide 500 mg IV (dislodges embolus downstream)
CRVO 'Blood and Thunder'
Massive retinal venous thrombosis: diffuse flame hemorrhages in all 4 quadrants + tortuous dilated veins + cotton wool spots
Amaurosis Fugax Warning
Transient monocular vision loss lasting 5–15 minutes ('curtain pulled down and up') = CAROTID ATHEROEMBOLISM herald before major stroke
Bottom-Line Clinical Pearl
Central Retinal Artery Occlusion (CRAO) is an OPHTHALMIC ISCHEMIC STROKE characterized by sudden, catastrophic, painless monocular vision loss (often counting fingers or light perception only). Fundoscopy reveals a pale, milky, edematous ischemic retina with a pathognomonic 'CHERRY-RED SPOT' at the fovea (where the thin fovea allows underlying vascular choroid to shine through) and 'boxcarring' of retinal arterial blood columns. In elderly patients (> 50 years), always check ESR and CRP to rule out arteritic CRAO from GIANT CELL ARTERITIS (GCA); if suspected, administer IV Methylprednisolone (1,000 mg/day) immediately to save the contralateral eye! Embolic non-arteritic CRAO requires immediate stroke center transfer, 12-lead ECG (atrial fibrillation), carotid ultrasound, and acute IOP-lowering maneuvers (ocular massage, Timolol, IV acetazolamide). Central Retinal Vein Occlusion (CRVO) presents with subacute, painless vision loss; fundoscopy reveals the classic 'BLOOD AND THUNDER' appearance (diffuse retinal hemorrhages and optic disc edema).
The central retinal artery is the primary branch of the ophthalmic artery (derived from the internal carotid artery), providing end-arterial perfusion to the inner two-thirds of the retina. The fovea, however, receives additional dual circulation from the deeper short posterior ciliary arteries (choroid).
Occlusion occurs due to: (1) Calcific/cholesterol emboli (Hollenhorst plaques) originating from ipsilateral internal carotid stenosis, (2) Fibrin-platelet cardioembolism from atrial fibrillation or endocarditis, or (3) Arteritic vasculitis (Giant Cell Arteritis/Temporal Arteritis) in elderly patients. Retinal neurons suffer irreversible ischemic necrosis within 90 to 240 minutes of complete circulatory cessation.
| Physical & Fundoscopic Exam | Diagnostic Findings in CRAO | Pathophysiologic Rationale |
|---|---|---|
| Visual Acuity | Severe, profound drop in vision (typically limited to counting fingers, light perception, or total darkness) | Complete ischemia of retinal ganglion cells and inner nuclear layers. |
| Pupillary Exam | Prominent Relative Afferent Pupillary Defect (RAPD/Marcus Gunn pupil) | Defective sensory input from the infarcted retina. |
| Retinal Parenchyma | Diffuse pale, opaque, milky-white, ground-glass retina | Acute intracellular cytotoxic axonal edema of the ganglion cell layer obscuring underlying choroid. |
| Fovea Centralis | Pathognomonic 'Cherry-Red Spot' | The fovea lacks the ganglion cell layer and is nourished entirely by the deeper choroidal circulation, allowing the bright red vascular choroid to show through. |
| Retinal Arterioles | 'Boxcarring'/cattle-trucking of blood columns; visible bright refractile Hollenhorst plaques at arterial bifurcations | Stasis and segmentation of red blood cell columns within narrowed, non-pulsatile arterioles. |
Central Retinal Vein Occlusion (CRVO) is caused by thrombosis of the central retinal vein at or near the lamina cribrosa of the optic nerve, where the artery and vein share a common adventitial sheath. Risk factors include advanced age, hypertension, diabetes mellitus, hypercoagulable disorders, and glaucoma. Outflow obstruction causes massive hydrostatic venous backpressure, producing vascular engorgement, diffuse retinal edema, and capillary rupture.
| Clinical Parameter | Central Retinal Artery Occlusion (CRAO) | Central Retinal Vein Occlusion (CRVO) |
|---|---|---|
| Speed of Vision Loss | Instantaneous/Hyperacute (seconds to minutes) | Subacute/Rapid over hours to days (often noticed upon waking in morning) |
| Fundoscopic Appearance | Pale, milky-white retina with Cherry-Red Spot and thin thread-like arterioles | 'Blood and Thunder' fundus: widespread diffuse flame-shaped and blot hemorrhages across all 4 retinal quadrants, massive optic disc edema, and engorged tortuous veins |
| Emergency Management | Acute stroke workup; emergent IOP lowering; rule out Giant Cell Arteritis (ESR/CRP) | Urgent ophthalmology referral for anti-VEGF intraocular injections and panretinal photocoagulation to prevent neovascular glaucoma ('90-day glaucoma') |
Test Your Retinal Artery & Vein Occlusions Clinical Acumen
Directly launch an active-recall practice block from our 8,400+ validated COMLEX Level 1, 2-CE & 3 board question bank with complete explanations.
Related Emergency Protocols & Differentials
Acute Ischemic & Hemorrhagic Stroke
Acute stroke code protocols and tissue plasminogen activator.
Open Protocol Related EM ProtocolAcute Angle-Closure Glaucoma & Ocular Hypertension
Differential diagnosis of sudden vision loss and pain.
Open Protocol Related EM ProtocolCranial Nerve Palsies & Neuro-Ophthalmology
Optic neuritis and ischemic optic neuropathies.
Open Protocol