Decreased vision, ocular or periorbital pain, afterimages or prolonged recovery of vision after exposure to bright light, may have a history of transient monocular visual loss (amaurosis fugax). Usually unilateral, although up to 20% of cases can be bilateral. Typically occurs in patients aged 50 to 80 years. Men outnumber women 2:1.

Critical

Although retinal veins are dilated and irregular in caliber, they are typically not tortuous. The retinal arterioles are narrowed. Associated findings include midperipheral retinal hemorrhages (80%), NVI (66%), NVD (35%), and NVE (8%).

Other

External collateral vessels on the forehead, episcleral injection, corneal edema, mild anterior uveitis, neovascular glaucoma, iris atrophy, cataract, retinal microaneurysms, CWSs, spontaneous pulsations of the central retinal artery, and cherry-red spot. CRAO may occur.

• CRVO: Diffuse retinal hemorrhages. Dilated and tortuous retinal veins. Decreased vision after exposure to light and orbital pain are not typically found. Ophthalmodynamometry and IVFA may aid in differentiating OIS from CRVO. See 11.8, Central Retinal Vein Occlusion.

• Diabetic retinopathy: Bilateral, usually symmetric. Hard exudates are often present. See 11.12, Diabetic Retinopathy.

• Aortic arch disease: Caused by atherosclerosis, syphilis, or Takayasu arteritis. Produces a clinical picture identical to OIS, but usually bilateral. Examination reveals absent arm and neck pulses, cold hands, and arm muscle spasms with exercise.

• Ipsilateral carotid artery disease: Usually ≥90% stenosis.

• Ipsilateral ophthalmic artery disease: Less common.

• Ipsilateral central retinal artery obstruction: Rare.

• Giant cell arteritis: Rare.

1. History: Previous episodes of transient monocular visual loss? Cold hands or arm muscle spasms with exercise?

2. Complete ocular examination: Search carefully for anterior chamber flare, asymmetric cataract, and NVI/NVA/NVD/NVE.

3. Medical examination: Evaluate for HTN, diabetes, and atherosclerotic disease. Check pulses. Cardiac and carotid auscultation. 

4. Laboratory workup for GCA in the appropriate settings. See 10.17, Arteritic Ischemic Optic Neuropathy (Giant Cell Arteritis).

5. Consider IVFA for diagnostic purposes.

6. Noninvasive carotid artery evaluation: Duplex Doppler US, oculoplethysmography, magnetic resonance angiography, others.

7. Consider orbital color Doppler US.

8. Consider ophthalmodynamometry if CRVO diagnosis cannot be excluded.

9. Carotid arteriography is reserved for patients in whom surgery is to be performed.

10. Consider cardiology consultation, given the high association with cardiac disease.

1. Carotid endarterectomy for significant stenosis. Refer to neurovascular surgeon.

2. Consider PRP and anti-VEGF agents in the presence of neovascularization.

3. Manage glaucoma if present. See 9.13, Neovascular Glaucoma.

4. Control HTN, diabetes, and cholesterol. Refer to internist.

5. Lifestyle modification (e.g., smoking cessation).

Depends on the age, general health of the patient, and the symptoms and signs of disease. Surgical candidates should be evaluated urgently.