Branch Retinal Vein Occlusion With Macular Edema

A 74-year-old woman had difficulty with reading for long periods. Recently, her vision seemed "milky." The patient was taking no medications; she had no significant medical history other than allergies to penicillin, codeine, and erythromycin.

The patient's best-corrected visual acuity was 20/400 in the right eye and 20/30 in the left eye. Pinhole testing improved vision in the right eye to 20/200. All lines on the Amsler grid appeared wavy when viewed with the right eye. Testing of the left eye showed no scotomas or metamorphopsia.

Intraocular pressures were normal; there was no afferent pupillary defect. Moderate nuclear sclerotic cataracts were present in both eyes. A dilated fundus examination of the right eye identified an inferotemporal branch retinal vein occlusion with secondary macular edema. The left fundus was unremarkable.

Leonid Skorin, Jr, DO, of Albert Lea, Minn, writes that a branch retinal vein occlusion occurs at an arteriovenous crossing as a result of compression of the vein by its adjacent atherosclerotic arteriole. This condition develops most often in persons older than 50 years who may have generalized arteriosclerotic disease and its predisposing factors. Evaluate affected patients for systemic hypertension, cardiovascular disease, diabetes, and hyperlipidemia.

This patient's blood pressure was normal. A stress test identified an abnormal flow reserve, for which 81 mg of aspirin daily was prescribed. Blood glucose level was normal. C-reactive protein and homocysteine levels were elevated: 4.6 mg/L (normal, less than 3 mg/L) and 49 µmol/L (normal, 13 µmol/L or lower), respectively. A daily folic acid, vitamin B₆, vitamin B₁₂ combination dietary supplement was prescribed. The lipid profile also showed abnormalities: total cholesterol, 208 mg/dL; triglycerides, 262 mg/dL; high-density lipoprotein cholesterol, 45 mg/dL; low-density lipoprotein cholesterol, 111 mg/dL. Lovastatin, 20 mg/d, was started. She was also encouraged to eat more vegetables and salads and reduce her intake of meat and starches.

Retinal hemorrhages may take up to a year to resolve. Even with treatment, not all patients recover their vision. When macular edema persists (as in this patient), focal argon laser photocoagulation is required. (Panretinal photocoagulation is reserved for patients in whom neovascularization develops.) An intravitreous corticosteroid (eg, triamcinolone) injection may be used as adjunctive therapy for macular edema. Because of the marked macular edema and poor visual acuity, this patient underwent both treatments. Six months later, the macula showed markedly less edema; however, the patient's vision did not improve.