Central retinal artery occlusion (CRAO)
Branch retinal artery occlusion (BRAO)
Etiology
Arterial hypertension, embolism (cardiac/carotid artery), thrombosis, giant cell arteritis, collagen vascular diseases (polyarteritis nodosa, SLE), hypercoagulable states (polycythemia, antiphospholipid antibodies, oral contraceptives), sickle cell disease, syphilis
Differential diagnosis
Ophthalmic artery occlusion (no cherry-red spot) > same treatment as for CRAO
AION, certain lipid storage diseases (e.g. Tay-Sachs)
History
- Unilateral, acute, painless loss of vision (counting fingers to light perception in 94%)
- Since when? CAUTION: lysis window of < 4 hours
- Preceding TIA/amaurosis fugax?
- Jaw claudication/scalp tenderness/headache? > AION
- Underlying rheumatologic disease?
Findings/examinations
- Subjective visual acuity testing (loss of vision)
- RAPD (before fundoscopy)
- IOP
- Motility restrictions
- Central visual field (finger perimetry) > horizontal defect
- Anterior segment
- Fundus in mydriasis (pale/whitened retina, cherry-red spot of the macula/cilioretinal sparing, embolus possibly visible in a vessel/vessels/hemorrhages)
- OCT (retinal swelling/blurring of the inner retinal layers)
Approach
Rapid action in CRAO is essential -> confirm the diagnosis by examination
Acute
< 4.5 hours since onset
- Indication for thrombolysis: treatment initiated < 4.5 hours after onset, no improvement in vision
-> Emergency telephone referral to the stroke unit of a tertiary hospital (not via the eye clinic!)
- IOP lowering with Diamox 250mg tablet p.o., timolol eye drops or Cosopt and/or Iopidine eye drops
- Anterior chamber paracentesis if IOP does not fall below 10 mmHg
- Ocular massage for 3–5 min by a physician
- (Hyperventilation into a paper bag > vasodilation)
Subacute
From 4.5 hours since onset:
- Confirm the diagnosis (visual acuity, IOP, RAPD, initial assessment of the fundus with undilated pupil, OCT, fundus photograph)
- Emergency laboratory work-up: CRP/ESR > treatment as per GCA/temporal arteritis, complete blood count, AST/ALT, ALP, GGT, LDH, creatinine, glucose, INR
- ESR upper limit: men = age:2; women = (age+10):2
- Follow-up laboratory work-up: HbA1c, fasting lipids (LDL, HDL, cholesterol)
- Neurology co-assessment (stroke unit)
- Assess for cerebral ischemia
- Assess for contraindications to full-dose heparinization
- Further treatment (what, by whom) — see Treatment
- Internal medicine work-up to rule out cardiovascular risk factors
- Including vascular Doppler examination, ECG/possibly 24h Holter ECG
Treatment
- < 4 hours: emergency referral to the stroke unit of a tertiary hospital for thrombolytic therapy
- 4.5 hours (thrombolysis time window exceeded):
- Emergency referral to a tertiary hospital if needed for further work-up and possible hospital admission
- Prophylaxis: aspirin 100mg tablet 1x/day for 6 months (no evidence)
Prognosis
Complete CRAO: visual improvement in 15–25% with conservative, minimally invasive treatment (roughly equivalent to the average spontaneous course)
Follow-up
Examinations
Fundus in mydriasis, 10–20% develop neovascularization of the iris/optic nerve/angle/retina
Follow-up intervals
- 2–4 weeks
- 2–3 months with fluorescein angiography and kinetic visual field testing (fitness to drive)
- 6 months
Treatment
In case of neovascularization
- Panretinal laser photocoagulation/anti-VEGF
Sources: Will's Eye Manual, Eyewiki.org,
