section name header

Information

Editors

PetraIjäs
SatuKam
RonaldKam

Central Retinal Artery Occlusion

Essentials

  • The symptom is sudden, painless unilateral vision loss.
  • To confirm the diagnosis, the patient must be sent immediately to an ophthalmic emergency department with a unit treating cerebrovascular emergencies (stroke unit).
  • Central retinal artery occlusion is a form of acute cerebrovascular accident associated with a risk of retinal infarction and permanent vision loss.
  • Irreversible retinal damage starts to occur as soon as 1½ hours after the occlusion.
  • Time must not be lost inspecting the fundus (except for optical coherence tomography [OCT] at the ophthalmic emergency department).
  • Intravenous thrombolytic therapy within 4½ h from symptom onset should be considered in the emergency stroke unit with individual consideration of risks and benefits.
  • Mechanical interventions to dislodge the embolus, such as applying pressure to the eye or anterior chamber paracentesis are no longer recommended.

Aetiology and epidemiology

  • Rather uncommon, with an incidence of about 1.9 per 100 000 person years.
  • Risk factors include age, hypertension, dyslipidaemia, diabetes, smoking and obesity.
    • 40% of patients have significant carotid artery stenosis as an aetiological factor.
    • Causes of cardiac origin are also common (atrial fibrillation, valvular disease, heart failure).
  • About 10% of patients have had one or more episodes of amaurosis fugax Transient Ischaemic Attack (TIA).
    • TIA causing transient unilateral vision loss
    • May last from a few (3-5) minutes to an hour.
  • Giant cell arteritis must always be excluded as the sight may be saved in the fellow eye with glucocorticoid therapy. About 10% of patients with giant cell arteritis lose their vision due to central retinal artery occlusion Giant Cell (Temporal) Arteritis.

Symptoms and findings

  • Sudden, painless unilateral loss of vision or a visual field
  • Vision is usually reduced to the level of counting fingers or seeing hand movement or only light perception.
    • Central vision may be spared by a cilioretinal artery (occurs in about 18% of the population), which supplies the macula.
  • In branch retinal artery occlusion, changes are only present peripherally to the occlusion with a corresponding partial visual field deficit.
  • A relative afferent pupillary defect (RAPD) can nearly always be detected.
    • When light is shone in the right and left eyes alternately, both for an equal length of time, without a break between the eyes:
      • the indirect pupillary light reflex will cause constriction of the pupils in both eyes when shining the light in the normal eye, and
      • both pupils will become dilated when the light is shifted quickly from the normal eye to the affected eye.
    • If the RAPD test can be done reliably, a negative test result will exclude central retinal artery occlusion with nearly full certainty.
  • It is important not to lose time. Examination of the fundus should be left for an ophthalmologist (picture 1).
  • The best examination is macular OCT, which usually is available, at least, in ophthalmology units of major secondary care hospitals.
    • At first, OCT may be the only imaging method to detect the abnormality (ischaemic thickening of the inner retinal layers).

Treatment and further investigations

  • Any patient with sudden unilateral loss of vision should be referred immediately to an ophthalmic emergency department to confirm the diagnosis.
  • After confirming the diagnosis, the patient should be transferred immediately to an emergency unit treating cerebrovascular accidents (stroke unit) to assess the feasibility of thrombolytic therapy and for aetiological investigations.
  • Central retinal artery occlusion is comparable to acute cerebral infarction Cerebral Infarction (Ischaemic Stroke). There is a risk of retinal infarction and permanent vision loss. Irreversible retinal damage starts to occur as soon as 1½ hours after the occlusion.
  • Intravenous thrombolytic therapy within 4½ h may improve the visual prognosis.
    • It is considered individually weighing the risks and benefits.
    • It is carried out as for patients with cerebral infarction Cerebral Infarction (Ischaemic Stroke).
    • There is no evidence of the benefits of thrombolytic therapy from randomized controlled trials. Case series and meta-analyses suggest it may improve the visual prognosis.
  • Mechanical interventions, such as applying pressure to the eye or anterior chamber paracentesis, were previously recommended to move the embolus further. Today, these are not believed to be beneficial and may even worsen the visual prognosis.
  • Without treatment, the prognosis of central retinal artery occlusion is poor.
  • Patients often have an undiagnosed disease requiring urgent treatment (such as concomitant cerebral infarction, carotid artery stenosis, hypertensive crisis, fresh myocardial infarction or critical structural heart disease).
  • Long-term secondary prevention of cerebrovascular occlusion should mainly be carried out as for patients with cerebral infarction or TIA Transient Ischaemic Attack (TIA) Cerebral Infarction (Ischaemic Stroke).
  • If a Hollenhorst crystal (cholesterol embolus in an artery in the fundus, detected in fundus photograph or ophthalmological examination) is found in an asymptomatic person, aetiological investigations (echography of carotid arteries and investigation of cardiovascular risk factors) and the planning and implementation of secondary prevention can be carried out in primary health care. If significant carotid artery stenosis is detected, the patient should be referred to a vascular surgeon.

Follow-up

  • After initial treatment and examination, eyes with central retinal artery occlusion require no routine follow-up. There is usually no risk of secondary neovascular glaucoma in association with retinal artery occlusion.
  • Nevertheless, it is often useful that the patient visits an ophthalmologist once in about one month from the emergency to check the other eye at a calm stage.
    • Sometimes, a chronic disease, such as diabetic retinopathy Diabetic Retinopathy, cataract Cataract or glaucoma Glaucoma, can be detected in the other eye.
    • Patients often benefit from referral to a low vision rehabilitation counsellor.
  • As for any cardiovascular risk factors or secondary preventive medication, follow-up in primary health care is recommended every 1-2 years, for example.

Driving health

  • Due to differences in national and regional regulations, the information provided below may not be fully relevant in all settings. Always check and follow local policies. See also local instructions for medical assessment of driving health.
  • After recent unilateral loss of vision, a driving ban will be placed until further notice.
  • Local regulations should be followed as regards informing e.g. the police of the change to driving health.
  • After unilateral loss of vision, a repeat assessment of driving health requirements can be done by an ophthalmologist no earlier than 6 months after loss of vision.
  • In addition, a driving test must be taken and approved to confirm driving health.

    References

    • Lin JC, Song S, Ng SM, et al. Interventions for acute non-arteritic central retinal artery occlusion. Cochrane Database Syst Rev 2023;1(1):CD001989 [PubMed]
    • Mac Grory B, Schrag M, Biousse V, et al. Management of Central Retinal Artery Occlusion: A Scientific Statement From the American Heart Association. Stroke 2021;52(6):e282-e294 [PubMed]
    • Balal S, J'Bari AS, Hassan A, et al. Capturing the Occult Central Retinal Artery Occlusion Using Optical Coherence Tomography. Curr Eye Res 2021;46(11):1762-1767 [PubMed]
    • Lavin P, Patrylo M, Hollar M, et al. Stroke Risk and Risk Factors in Patients With Central Retinal Artery Occlusion. Am J Ophthalmol 2019;200():271-272 [PubMed]
    • Schrag M, Youn T, Schindler J, et al. Intravenous Fibrinolytic Therapy in Central Retinal Artery Occlusion: A Patient-Level Meta-analysis. JAMA Neurol 2015;72(10):1148-54 [PubMed]
    • Hayreh SS. Ocular vascular occlusive disorders: natural history of visual outcome. Prog Retin Eye Res 2014;41():1-25 [PubMed]
    • Schumacher M, Schmidt D, Jurklies B, et al. Central retinal artery occlusion: local intra-arterial fibrinolysis versus conservative treatment, a multicenter randomized trial. Ophthalmology 2010;117(7):1367-75.e1 [PubMed]