Central Retinal Artery Occlusion

Aka: Central Retinal Artery Occlusion, CRAO, Branch Retinal Artery Occlusion, BRAO, Acute Retinal Ischemia, Retinal Artery Occlusion

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II. Definitions

  1. Central Retinal Artery Occlusion (CRAO)
    1. Central Retinal artery is occluded affecting all Visual Fields
  2. Branch Retinal Artery Occlusion (BRAO)
    1. Branches of central Retinal artery are occluded, with segmental Vision Loss

III. Epidemiology

  1. Annual Incidence: One per 100,000 (U.S.)
  2. Age (mean): 60 years old

IV. Pathophysiology

  1. Retinal vascular supply
    1. Central Retinal artery
      1. Supplied by opthalmic artery (branch of the Internal Carotid Artery)
    2. Cilioretinal artery (only present in 30% of patients)
      1. May supply fovea of Retina (allowing for preserved central Vision despite CRAO)
  2. Causes: Ophthalmic Artery Occlusion
    1. See Transient Ischemic Attack
    2. Embolism to Retinal artery (most common CRAO cause)
      1. Cholesterol or thrombotic emboli (esp. Atrial Fibrillation)
    3. Temporal Arteritis (<5% of CRAO cases) or other Vasculitis
    4. Hypoperfusion
      1. Hemodialysis
      2. Severe shock
      3. Nocturnal artery Hypotension (awake with Vision Loss)
        1. Associated with Antihypertensives taken near bedtime
    5. Other causes
      1. Thrombosis, inflammation or Eye Trauma

V. Risk Factors

  1. Age over 70 years
  2. Atrial Fibrillation
  3. Cardiovascular disease risks
    1. Coronary Artery Disease
    2. Diabetes Mellitus
    3. Hypertension
    4. Hyperlipidemia
    5. Hypercoagulable state
    6. Tobacco Abuse
  4. Migraine Headaches
  5. Collagen vascular disease (e.g. Systemic Lupus Erythematosus)
  6. Temporal Arteritis
  7. Sickle Cell Anemia

VI. Symptoms

  1. See Transient Monocular Blindness (Amaurosis Fugax)
  2. Painless acute unilateral Vision Loss
    1. More than half of patients have only hand motion and light Perception
    2. CRAO causes Vision Loss over entire Visual Field, while BRAO results in focal Vision Loss
    3. May be preceded by prior episode of Amaurosis Fugax
  3. May be associated with other focal neurologic deficits
    1. See Transient Ischemic Attack
    2. Affects ipsilateral Carotid Artery circulation

VII. Signs

  1. Visual Acuity severely reduced to counting fingers, hand motion or light Perception only
    1. Branch Retinal Artery Occlusion (BRAO) may present with Visual Field cut
    2. Perform full Visual Field testing (differentiates CRAO from BRAO)
  2. Relative Afferent Pupillary Defect
    1. Pupil dilated with slow reaction (but preserved Consensual Light Reaction)
  3. Fundoscopic exam
    1. Retina appears pale-gray or white due to Retinal edema
    2. Macula with cherry-red spot on white-yellow background (collateral circulation from Choroid)
    3. Constricted arterioles
    4. Box-Carring of Retinal vessels
      1. Retinal vessels with interrupted columns of blood appear as train box cars
      2. Blood cells separate from serum
    5. Hollenhorst Plaques (white punctate Cholesterol emboli)
      1. "Glistening orange yellow flakes"
      2. Represent fragmented emboli at arteriole bifurcations
  4. Remainder of Eye Exam is normal
    1. Normal Extraocular Movement
    2. Normal ocular pressure
    3. Normal anterior chamber
  5. Neck Exam
    1. Carotid Bruit

VIII. Exam

  1. Vital Signs including Blood Pressure
  2. Complete Neurologic Exam
    1. Include NIH Stroke Scale
  3. Cardiovascular Exam
  4. Complete Eye Exam
    1. See Acute Vision Loss
    2. See Eye Vital Signs
    3. Visual Fields and Visual Acuity testing drive management and prognosis

IX. Differential Diagnosis

  1. See Acute Vision Loss
  2. Central Retinal Vein Occlusion
  3. Retinal Detachment
  4. Vitreous Hemorrhage
  5. Acute Angle Closure Glaucoma

X. Precautions

  1. Central Retinal Artery Occlusion (CRAO) is a stroke of the eye
  2. Evaluate as Cerebrovascular Accident (code stroke in hyperacute presentations)
    1. In some centers, CRAO presenting within first 4.5 hours, is treated with tPA

XI. Labs

  1. Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (cRP)
    1. Increased in Temporal Arteritis
  2. Cerebrovascular Accident Evaluation
    1. Acute Retinal Artery Occlusion is managed as an acute eye CVA and typically involves CVA-related lab testing
    2. Complete Blood Count with Platelets
    3. Comprehensive Metabolic Panel
    4. Coagulation Studies (INR, PTT)
    5. Lipid Panel
    6. Hemoglobin A1C

XII. Diagnostics

  1. Electrocardiogram
    1. Evaluate for Atrial Fibrillation
  2. Echocardiogram
    1. Evaluate as performed in CVA and TIA

XIII. Imaging: Acute

  1. CT Head and CT Angiogram Head and Neck
    1. Evaluate as Transient Ischemic Attack or CVA (depending on deficits and timing)
    2. Performed as stat CVA imaging in acute presentations
  2. MRI Brain with Diffusion Weighted Imaging
    1. Consider for other associated embolic lesions, or in delayed presentations
    2. Include MR Angiogram if CT angiogram not already performed
  3. Orbital Ultrasound
    1. Exclude alternative diagnoses of Acute Vision Loss (Retinal Detachment, Vitreous Hemorrhage)
    2. Central Retinal artery loss of Doppler Ultrasound signal
    3. Retrobulbar spot sign
      1. Test Sensitivity: 59%
      2. Hyperechoic dot within central Retinal artery
      3. Positive in cases in which thromboembolic material is calcified
        1. Calcified emboli are poorly responsive to TPA
    4. References
      1. Broder (2021) Crit Dec Emerg Med 35(11): 12-3
      2. Nedelmann (2015) Stroke 46: 2322-4 [PubMed]
      3. Riccardi (2016) J Emerg Med 50: e183-5 [PubMed]

XIV. Management: General

  1. Manage in similar fashion to a stroke protocol (code stroke)
    1. Follow stroke evaluation with stat head imaging, ekg, labs for acute presentations
    2. Consider Thrombolytics in hyperacute presentations within 4.5 to 6 hours (see below)
  2. Emergent Ophthalmology Consultation without delay
    1. Irreversible Vision Loss begins in the first 90-120 minutes
  3. Temporal Arteritis (ESR or CRP meet criteria)
    1. See Temporal Arteritis
    2. Start empiric Corticosteroids
    3. Temporal artery biopsy or Doppler Ultrasound

XV. Management: Thrombolytics and Cerebrovascular Management

  1. Approach CRAO as a "stroke to the eye"
  2. Evaluate patients age <50 years old for Hypercoagulable state causes (e.g. Antiphospholipid Antibody Syndrome)
  3. Manage as acute CVA in presentations within 4.5 to 6 hours (considering tPA or TNK)
    1. Stroke neurologists and ophthalmologists recommend systemic Thrombolytics for CRAO in some centers
    2. Limited and mixed evidence, but >50% recovery with Thrombolytic use
  4. References
    1. Bustamante (2024) Eur Stroke J 9(2):486-93 +PMID: 38189284 [PubMed]
    2. Page (2018) Front Neurol 9:76 +PMID: 29527185 [PubMed]
    3. CRAO: Promising Results From Emergency Protocols (AAO)
      1. https://www.aao.org/eyenet/article/crao-emergency-protocols-may-preserve-vision

XVI. Management: Lower Intraocular Pressure or dislodge Occlusion

  1. Precautions
    1. Thrombolytics in the first 4.5 hours have the best evidence and these other measures are adjunctive only
    2. Hyperbaric oxygen may be considered where available
    3. Many of the historic measures in this list lack modern evidence of benefit, and are not recommended
      1. Balloting the eye
      2. Ocular Paracentesis
  2. Measures with supporting evidence
    1. Hyperbaric oxygen
      1. May improve Retinal oxygenation by increasing passive Choroidal oxygenation
      2. Reasonable to consider if available at treating facility
      3. Murphy-Lavole (2012) Undersea Hyperb Med 39(5): 943-53 +PMID: 23045923 [PubMed]
  3. Other Measures with evidence lacking
    1. Lie patient supine with both Eyelids closed
    2. Ballot the eye: Apply intermittent pressure to eyeball
      1. Emergently perform as soon as possible
        1. Offers benefit within 6 hours (possibly up to 24 hours)
      2. Massage the globe with index fingers or each hand, then release suddenly
      3. Apply pressure in repeated cycles of 5-10 seconds on and 5 seconds off
      4. Perform for 20 cycles total or from 5-30 minutes
      5. Goal is to dislodge a thrombus
        1. Aqueous outflow increases with eye pressure
        2. Retinal perfusion increases with release of eye pressure
    3. Ocular Paracentesis
      1. Ophthalmologist aspirates 0.1 to 0.4 ml anterior chamber fluid via 27-30 gauge needle
      2. Goal to reduce Intraocular Pressure and shift the embolism distally
      3. May offer benefit up to 24 hours after onset
    4. Consider Hypercarbia
      1. Patient rebreathes into a paper bag for 10 minutes of each hour OR
      2. Inhalation of mix of 5% carbon dioxide and 95% oxygen
      3. Goal is to result in eye vessel vasodilation due to increased carbon dioxide concentrations
    5. Consider Aqueous Humor production strategies
      1. Mannitol 1 g/kg IV for 1 dose AND Acetazolamide 500 mg IV for 1 dose OR
      2. Acetazolamide 500 mg orally for 1 dose
    6. Other measures that have been used (discuss with ophthalmology)
      1. Timolol maleate (0.5%) one drop topically
      2. Pilocarpine drops to eye
      3. Oral Nitroglycerin
      4. Pentoxifylline (Trental) three 600 mg tablets daily
      5. Laser arteriotomy
      6. Embolectomy

XVII. Prognosis

  1. Vision Loss risk increases after 90 minutes (and esp. after 4 hours) of arterial Occlusion
  2. Spontaneous visual improvement may occur in first 7 days after onset
  3. Final Visual Acuity in affected eye <20/400

XVIII. References

  1. Hartmann (2016) Crit Dec Emerg Med 30(6): 3-11
  2. Swaminathan and Marcolini (2025) Central Retinal Artery Occlusion, 2/17/2025
  3. Sales, Patel and Patel (2019) Crit Dec Emerg Med 33(12): 3-13
  4. Werner and St Peter in Herbert (2021) 21(9): 13-4
  5. Beatty (2000) J Accident Emerg Med 17:324-9 [PubMed]
  6. Biousse (2018) Ophthalmology 125:1597-607 [PubMed]
  7. Gelston (2020) Am Fam Physician 102(9):539-45 [PubMed]
  8. Pokhrel (2007) Am Fam Physician 76:829-36 [PubMed]

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