Central & Branch Retinal Vein Occlusions

Essentials of Diagnosis

• Sudden monocular loss of vision

• No pain or redness

• Widespread or sectoral retinal hemorrhages

General Considerations

• Common causes of acute vision loss

• Branch retinal vein occlusion is four times more common than central retinal vein occlusion

• The major predisposing factors are the etiologic factors in arteriosclerosis (diabetes mellitus, systemic hypertension, hyperlipidemia) and glaucoma

• In younger patients, consider estrogen therapy (including oral contraceptives), and inherited or acquired hypercoagulable states (thrombophilia) (see below)

• In bilateral retinal vein occlusions, consider hyperviscosity syndromes related to myeloproliferative disorders (eg, Waldenström macroglobulinemia) (rare)

Symptoms and Signs

• Central vein occlusion

  • Ophthalmoscopic signs include

    • Widespread retinal hemorrhages

    • Retinal venous dilation and tortuosity

    • Retinal cotton-wool spots

    • Optic disk swelling

  • Branch retinal vein occlusions may present in a variety of ways

    • Sudden loss of vision may occur at the time of occlusion if the fovea is involved or some time afterward from vitreous hemorrhage due to retinal new vessels (neovascularization)

    • More gradual visual loss may occur with development of macular edema

    • In acute cases, the retinal abnormalities (hemorrhages, venous dilation and tortuosity, and cotton-wool spots) are confined to the area drained by the obstructed vein

• Check blood pressure

• Ask about tobacco use

• Ask women about estrogen therapy (including oral contraceptives)

• Patients should also be asked about a history of glaucoma; intraocular pressure should be measured to assess for signs of open- or narrow-angle glaucoma

Laboratory Tests

• Obtain screening studies for diabetes mellitus, hyperlipidemia, and hyperviscosity

• In younger patients, consider tests for congenital or acquired hypercoagulable states (thrombophilia)

  • Antiphospholipid antibody syndrome (lupus anticoagulant)

  • Activated protein C resistance/Factor V Leiden

  • Protein C, protein S deficiency

  • Antithrombin deficiency

  • Hyperprothrombinemia (G20210A prothrombin gene mutation)

  • Increased factor VIII activity

  • Hyperhomocysteinemia

Therapeutic Procedures

• Panretinal laser photocoagulation (prophylactically or as soon as there is evidence of neovascularization) can be used to treat eyes at risk for neovascular glaucoma following ischemic central retinal vein occlusion

• Intravitreal injections of bevacizumab, an inhibitor of vascular endothelial growth factor (VEGF), achieve regression of iris neovascularization

• Retinal laser photocoagulation

  • May be indicated in chronic macular edema due to branch but not central retinal vein occlusion

  • Should be done when branch retinal vein occlusion is complicated by retinal neovascularization

• Intravitreal injection of a vascular endothelial growth factor (VEGF) inhibitor (such as ranibizumab [Lucentis], bevacizumab [Avastin], or aflibercept [VEGF Trap-Eye, Eylea]) is beneficial in patients with macular edema due to either branch or central retinal vein occlusion

• Intravitreal triamcinolone improves vision in chronic macular edema due to nonischemic central retinal vein occlusion

• Intravitreal implant containing dexamethasone

  • Beneficial in both central and branch retinal vein occlusion

  • However, carries the risk of glaucoma in 20–65% of patients

  • Causes cataract in all patients who have not already had cataract surgery

Complications

• Risk of neovascular (rubeotic) glaucoma is high if central retinal vein occlusion is associated with

  • Widespread retinal ischemia, manifesting as poor visual acuity (20/200 [6/60] or worse)

  • Florid retinal abnormalities

  • Extensive areas of capillary closure on fluorescein angiography

• Branch retinal vein occlusion may be complicated by peripheral retinal neovascularization or chronic macular edema

Prognosis

• In central retinal vein occlusion, severity of visual loss is a good guide to visual outcome

  • Initial visual acuity of 20/60 (6/18) or better indicates a good prognosis

  • Visual prognosis is poor for eyes with neovascular glaucoma

• In branch retinal vein occlusion, visual outcome is determined by the severity of glaucoma and macular damage from hemorrhage, ischemia, or edema

When to Refer

• All patients with retinal vein occlusion should be referred urgently to an ophthalmologist