Diagnosis and Associated Risks Factors

Acute RVO patients most commonly present with painless, blurred vision, vision loss or floaters.¹ The initial exam should include visual acuity, pupillary assessment, slit-lamp exam looking for new iris vessels, and gonioscopy for evaluation of the iridocorneal angle.² Dilated fundus exam may reveal intraretinal hemorrhages, dilated and tortuous retinal veins, retinal edema, exudates and cotton wool spots.³ As RVO patients may also have elevated ocular perfusion pressure or arteriovenous nicking with focal narrowing, optic nerve head (ONH) evaluation is necessary for all RVO patients to rule out glaucoma.³ Color and red-free fundus photography is useful to document the severity of the retina findings.⁴

Optical Coherence Tomography (OCT) is used to determine retinal thickness, monitor macular edema and vitreoretinal interface changes.² Treatment decisions are commonly based on OCT measurements because they are objective and quantifiable.² Visualization of microvasculature of the retina and choroid is possible utilizing Optical Coherence Tomography Angiography (OCTA), a non-invasive way to detect capillary nonperfusion, enlarged avascular zones and vascular abnormalities.² Fluorescein angiography is useful in assessing retinal ischemia, delayed vein filling, the presence of retinal neovascularization with fluorescein leakage and collateral vessels.⁴

Clinicians need to educate their patients about risk factors that increase their chances of developing an RVO. Linkage of RVO to certain systemic vascular risks including hypertension, hyperlipidemia, diabetes, active smoking and peripheral vascular disease has been made.^3,5-7 A meta-analysis found that 47.9% of RVO cases were attributed to hypertension, 20.1% to hyperlipidemia and 4.9% to diabetes.^3,8 Hypertension can cause a thickening or hardening of the overlying artery which causes turbulent blood flow that is believed to promote venous thrombosis.⁹ The occlusion can obstruct blood flow and increase venous pressure.^2,10 This may lead to vascular leakage and edema, hemorrhages and ischemia.⁹

Fifty-eight percent of patients with CRVO onset at an age younger than 50 were found to have a nontraditional risk factors, such as an underlying systemic disease, hypercoagulability or history of hormonal contraceptives on evaluation.¹¹ In a cohort with systemic lupus erythematosus, the incidence of CRVO was 3.5 times higher than in a control population.^10,11 Although men and women are affected equally, the incidence of RVO increases with age, with > 50 % of cases occurring in patients over 65 years old.⁹

Systemic factors that protect against BRVO include increased high density lipoprotein (HDL) levels, moderate alcohol consumption and increased exercise.³ In contrast, only increased physical activity has been shown to protect against CRVO.^3,6 Communication with the primary care provider is essential, since patients with RVO may have a higher risk of cardiovascular disease and cerebrovascular accidents.^3,12