What should be done for an adult with potential underlying health conditions such as hypertension, diabetes, or glaucoma diagnosed with a blood clot in the retina of one eye?

Management of Retinal Blood Clot (Retinal Vascular Occlusion)

If you are diagnosed with a blood clot in the retina, you need urgent ophthalmologic evaluation within 24-48 hours to determine whether this is a retinal vein occlusion (RVO) or retinal artery occlusion (RAO), followed by immediate systemic workup to prevent stroke and vision loss in the other eye. 1

Immediate Actions Required

Emergency Evaluation for Arterial Occlusion

• If this is a retinal artery occlusion (sudden, severe vision loss), you need immediate referral to a stroke center or emergency department within 4.5-6 hours because this represents an eye "stroke" with 3-6% risk of cerebral stroke in the first 1-4 weeks and 20-24% concurrent stroke rate. 1, 2, 3
• For patients over 50 years old with arterial occlusion, immediate blood tests (ESR and CRP) must be obtained to rule out Giant Cell Arteritis (GCA), which requires emergency high-dose corticosteroids to prevent blindness in the other eye. 1, 4, 3

Urgent Evaluation for Venous Occlusion

• If this is a retinal vein occlusion (more gradual vision loss with hemorrhages), you need ophthalmologic examination every 4-6 weeks for the first 6 months to monitor for neovascularization that can cause devastating neovascular glaucoma. 1
• This includes slit-lamp examination and undilated gonioscopy to detect iris or angle neovascularization. 1

Critical Systemic Workup

Cardiovascular and Stroke Risk Assessment

• All patients with retinal vascular occlusion need urgent cardiovascular evaluation because up to 70% have clinically significant carotid stenosis, and the mortality rate is higher than age-matched controls due to cardiovascular disease. 1
• Brain MRI with diffusion-weighted imaging should be performed within 7 days, as 19-25% of patients have silent brain infarctions that predict future stroke risk. 1

Risk Factor Optimization

The following conditions must be identified and aggressively managed: 1

• Hypertension (most common risk factor for branch retinal vein occlusion)
• Diabetes mellitus (major risk factor for both arterial and venous occlusions)
• Hyperlipidemia (associated with retinal emboli and vascular disease)
• Glaucoma (most common ocular association with central retinal vein occlusion)
• Carotid artery disease (present in 45% of arterial occlusion patients)
• Sleep apnea (risk factor for central retinal vein occlusion)
• Smoking cessation (critical modifiable risk factor)

Special Considerations for Younger Patients

• If you are under 50 years old, additional testing for vasculitis and hypercoagulability disorders (protein C, protein S, antithrombin III, antiphospholipid antibodies, homocysteine levels) should be performed, though the cost-effectiveness remains controversial. 1, 2

Vision-Threatening Complications Requiring Treatment

Macular Edema Management

For retinal vein occlusion with macular edema causing vision loss: 1, 5

• Intravitreal anti-VEGF injections (ranibizumab) are FDA-approved and effective for macular edema following retinal vein occlusion
• Macular grid laser photocoagulation is proven effective for branch retinal vein occlusion with visual acuity of 20/40 or worse
• Intravitreal steroids are an alternative treatment option

Neovascularization Prevention and Treatment

If neovascularization develops (new abnormal blood vessels): 1

• Panretinal photocoagulation (PRP) laser is the standard treatment to prevent progression to neovascular glaucoma and vitreous hemorrhage
• Anti-VEGF injections can be used as adjunct therapy, especially when vitreous hemorrhage limits laser visibility
• This complication occurs in approximately 25% of central retinal vein occlusion patients

Fellow Eye Risk and Long-Term Monitoring

Risk of Second Eye Involvement

• With central retinal vein occlusion, you have a 1% per year risk of developing the same condition in the other eye. 1
• With branch retinal vein occlusion, you have a 10% risk of developing any type of retinal vein occlusion in the other eye over 3 years. 1

Ongoing Surveillance

• Regular ophthalmologic examinations are essential for life
• Continued monitoring of systemic risk factors with your primary care physician
• Immediate return if new visual symptoms develop in either eye

Critical Pitfalls to Avoid

Do not delay evaluation thinking vision will spontaneously improve - while some branch retinal vein occlusions show spontaneous improvement (37% gain two or more lines), arterial occlusions have less than 10% meaningful recovery without treatment, and both require urgent systemic evaluation. 1

Do not assume absence of visible emboli rules out embolic disease - the embolus may have fragmented or passed through, and cardiovascular workup is still mandatory. 1

Do not ignore asymptomatic retinal emboli if found - these carry increased stroke risk independent of conventional risk factors and warrant full cardiovascular evaluation. 1, 6