Retinal Vein Occlusion

 

🩸 Retinal Vein Occlusion (RVO)

A common vascular disorder of the retina resulting in vision loss due to blockage of retinal venous outflow.

🔍 Definition

Retinal vein occlusion occurs when a retinal vein becomes blocked, leading to venous stasis, hemorrhage, and edema of the retina, especially the macula.



🧠 Types of RVO

TypeDescription
Central Retinal Vein Occlusion (CRVO)Obstruction of the central retinal vein at the optic nerve
Branch Retinal Vein Occlusion (BRVO)Obstruction of a smaller branch vein, usually at an arteriovenous (AV) crossing
Hemispheric RVOAffects either the superior or inferior half of the retina

📊 Risk Factors

  • Hypertension (most common)

  • Diabetes mellitus

  • Hyperlipidemia

  • Glaucoma

  • Smoking

  • Hypercoagulable states (e.g., Protein C/S deficiency, antiphospholipid syndrome)

  • Older age (>50)

  • Oral contraceptives, especially in young women

⚙️ Pathophysiology

  • Vein compression (at AV crossing) → Turbulent flow → Endothelial damage → Thrombosis

  • Leads to:

    • Retinal hemorrhages

    • Macular edema

    • Venous dilation

    • Cotton wool spots

    • Ischemia and neovascularization (severe cases)

👁️ Clinical Features

SymptomDetails
Sudden, painless vision lossUsually unilateral
Visual blurring or distortionMay be partial or complete
FloatersIf vitreous hemorrhage occurs (late stage)
MetamorphopsiaIf macula is involved

🔬 Fundoscopy Findings

🔴 CRVO: "Blood and Thunder" Appearance

  • Diffuse retinal hemorrhages in all 4 quadrants

  • Dilated, tortuous veins

  • Optic disc edema

  • Cotton wool spots

  • Macular edema

🔵 BRVO: Sectoral Involvement

  • Hemorrhages limited to 1 quadrant or wedge-shaped area

  • Most common in superotemporal quadrant

  • Associated with AV crossing changes

🧪 Investigations

  • OCT → Detects macular edema and retinal thickness

  • Fluorescein Angiography (FA) → Identifies ischemic areas, leakage

  • OCT-Angiography → Non-invasive imaging of blood flow

  • Blood tests (in young patients or recurrent cases):

    • CBC, FBS, Lipid profile, Coagulation panel

    • Antiphospholipid antibodies, Homocysteine, ANA, ESR

💊 Treatment

🌟 Main Goals

  1. Reduce macular edema

  2. Prevent neovascular complications

  3. Manage systemic risk factors

🧪 Medical Therapy

🔹 Anti-VEGF Injections (first-line)

  • Ranibizumab (Lucentis)

  • Aflibercept (Eylea)

  • Bevacizumab (Avastin)
    ➡️ Reduce macular edema and improve visual acuity

🔸 Intravitreal Steroids

  • Dexamethasone implant (Ozurdex)

  • Triamcinolone acetonide ➡️ Used in refractory cases or if anti-VEGF contraindicated

🔦 Laser Treatment

  • Focal/Grid Laser Photocoagulation: For BRVO with macular edema

  • Panretinal Photocoagulation (PRP): For ischemic CRVO/BRVO with neovascularization

🧑‍⚕️ Systemic Management

  • Control BP, blood sugar, and lipids

  • Stop smoking

  • Antiplatelet therapy not routinely recommended, but evaluate clotting disorders in young patients

🚨 Complications

  • Neovascular glaucoma (especially in ischemic CRVO)

  • Vitreous hemorrhage

  • Macular ischemia (irreversible vision loss)

  • Retinal detachment

📝 Summary Table

FeatureCRVOBRVO
Area AffectedEntire retinaSectoral (1 quadrant)
Vision LossSudden, severeVariable, milder
HemorrhagesDiffuse ("blood and thunder")Sectoral
EdemaCommonCommon
TreatmentAnti-VEGF, steroids, PRPAnti-VEGF, focal laser

Let me know if you'd like:

  • A visual diagram of CRVO vs. BRVO

  • Flashcards or MCQs

  • A case study example for better understanding!

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