What is the likely diagnosis for an older adult with a history of hypertension or diabetes presenting with a curtain over the visual field, arteriovenous (AV) nicking, cotton wool spots, flame-shaped hemorrhages, and an increased cup-to-disc ratio?

Retinal Vein Occlusion (Branch or Central)

The clinical presentation of a "curtain over the visual field" with arteriovenous nicking, cotton wool spots, flame-shaped hemorrhages, and increased cup-to-disc ratio in an older adult with hypertension or diabetes is most consistent with a retinal vein occlusion (RVO), specifically branch retinal vein occlusion (BRVO) if the findings are sectoral or central retinal vein occlusion (CRVO) if diffuse. 1

Key Diagnostic Features

The constellation of findings points definitively toward RVO rather than other vascular retinopathies:

• "Curtain over visual field" represents the acute visual field defect corresponding to the area of retinal ischemia and hemorrhage characteristic of RVO 1
• Flame-shaped hemorrhages are the hallmark acute finding in RVO, occurring due to sudden venous outflow obstruction and increased hydrostatic pressure 1, 2
• Cotton wool spots indicate retinal ischemia from arteriolar occlusion at the borders of ischemic areas, signaling serious vascular disease 3, 4
• AV nicking reflects chronic hypertensive changes where the retinal artery (positioned anterior to the vein in 96.8% of cases) compresses the underlying vein at crossing points 5

Distinguishing from Diabetic Retinopathy

While diabetic retinopathy shares some features (cotton wool spots, hemorrhages), the acute "curtain" presentation and distribution pattern differ:

• Diabetic retinopathy typically presents with microaneurysms, dot-blot hemorrhages (not flame-shaped), and gradual vision loss rather than acute sectoral field defects 1
• RVO presents acutely with sudden visual symptoms, vascular tortuosity, venous dilation of affected veins, and sectoral distribution of findings 1
• The increased cup-to-disc ratio may represent either pre-existing glaucoma (a risk factor for CRVO) or developing neovascular glaucoma as a complication 1

Risk Factor Profile

The patient's hypertension is the critical risk factor:

• BRVO is strongly associated with arterial hypertension, hyperlipidemia, diabetes, and arteriovenous crossing changes 1
• AV nicking occurs predominantly when chronic hypertension causes the anterior artery to compress the underlying vein (96.8% of nicking sites) 5
• Older age is the main risk factor for both BRVO and CRVO 1

Immediate Management Priorities

Urgent Ophthalmologic Assessment

• Examine every 4-6 weeks for approximately 6 months to detect neovascularization, which develops in eyes with significant capillary nonperfusion 3
• Fluorescein angiography should be performed to evaluate extent of vascular occlusion, degree of ischemia, and localize areas of retinal non-perfusion or neovascularization 3, 2
• Optical coherence tomography (OCT) is the most sensitive method for detecting and monitoring macular edema, which commonly develops in RVO 3, 2

Systemic Evaluation

• Communicate with primary care physician regarding increased risk of cardiovascular events and all-cause mortality in RVO patients 2
• Control blood pressure immediately if malignant hypertension is present (bilateral cotton wool spots with flame hemorrhages typically occur with BP >200/120 mmHg) 3
• Assess for carotid occlusive disease and sleep apnea (CRVO risk factors) 1

Treatment Approach

For Macular Edema

• Anti-VEGF agents and/or intraocular corticosteroids are necessary if macular edema develops 3
• Macular edema causes substantial decrease in vision-related quality of life and requires prompt treatment 2

For Neovascularization

• Dense peripheral panretinal photocoagulation with adjunctive anti-VEGF agents may be necessary if neovascularization develops 3
• Eyes with BRVO and significant capillary nonperfusion can develop retinal neovascularization and vitreous hemorrhage 1
• Approximately 25% of CRVO patients develop iris neovascularization 1

Critical Pitfalls to Avoid

• Do not delay fluorescein angiography - the degree of capillary nonperfusion determines prognosis and guides treatment intensity 1, 3
• Do not assume cotton wool spots are benign - they are markers of retinal ischemia signaling serious underlying vascular disease requiring immediate systemic evaluation 3, 4
• Do not miss neovascular glaucoma - the increased cup-to-disc ratio warrants gonioscopy to evaluate for angle neovascularization 1
• Do not overlook fellow eye risk - patients with BRVO have 10% risk of developing RVO in the fellow eye over 3 years 1