Description, symptoms, signs, prevalence, significance, differential diagnosis, see also See Branch retinal vein occlusion – assessment.
Urgent Initial management relates to any underlying systemic disease or possible glaucoma. Treatment may help to reduce the risk of stroke (cerebrovascular accident) or an additional subsequent ocular vascular occlusion.
Btood tests Patients need a full blood work-up to treat any underlying systemic risk factors such as hypertension, diabetes, carotid stenosis or cardiovascular disease.
Oral medication Review antihypertensive and other medications, and consider daily aspirin. Consider discontinuing oral contraceptives if being present.
Ocular tests Risk factors for glaucoma should be evaluated, and intraocular pressure reduced if necessary. Assess for neovascularization of the disc or elsewhere on the retina. Neovascularization of the iris, anterior angle or neovascular glaucoma are rarer complications. Fluorescein angiography may be indicated to assess retinal capillary nonperfusion; the presence of an area of more than five disc diameters is a risk for development of neovascularization. Usually a fluorescein angiography is indicated 2-3 months after a BRVO, once the hemorrhages have cleared.
Laser treatment In many patients with BRVO, no laser treatment may be necessary. However, recognized indications are macular edema or neovascularization. Grid argon laser treatment for macular edema is indicated in the presence of:
- Reduced visual acuity (<20/40)
- Good macular perfusion, with intact capillaries evident on angiography
- Resolution of most of the adjacent hemorrhages (Branch Retinal Vein Occlusion Study or BRVOS).
The natural course of BRVO is associated with a relatively good prognosis in many cases. However, possible changes include:
- Collateral vessels may develop in the months after an occlusion to improve the blood flow away from the affected zone. Unlike neovascularization, collateral vessels are not leaky and are considered a beneficial change in the resolution of the BRVO.
- Arterial macroaneurysms result from focal damage to the vessel wall. They appear as an isolated swelling of the vessel and carry the risk of leakage(see BRVO – sequelae).
- Lipid (hard) exudates may be precipitated from the leaky vessels. They are dense, waxy and yellow in color, and usually preceded by retinal edema. Inthe macular area, the exudates may appear like a radiating star (see BRVO – sequelae).
- Other possible changes include neovascularization, vitreous hemorrhage, fibrosis, retinal detachment and, rarely, neovascular glaucoma.
Prevalence BRVO is the second most common vascular disease affecting the retina after diabetic retinopathy. Although, overall, vascular occlusions are uncommon (1 in 1000), they are relatively common (1 in 100) in specific at-risk groups, such as people aged over 50 years.
Significance BRVOs may be vision threatening, and also flag the risk of potentially life
Extensive hemorrhages associated with a superior temporal branch vein occlusion. The lipid exudates around the macula indicate that the occlusion has been present for several months.
Post-treatment fundus photograph of the same patient as in Fig. 18.1, taken 11 months later. Multiple focal areas of pigment epithelial atrophy secondary to laser burns are visible in the superior temporal quadrant.