The management of acute visual failure

Abstract

This review of acute visual failure covers the clinical manifestations and management of ocular strokes CRA occlusion, BRA occlusion and AION. The diagnostic process for each patient requires meticulous attention to: 1. Blood pressure, heart rate and rhythm, palpation of the temporal arteries, and auscultation of the heart, neck, eyes and head. 2. Dilated funduscopic examination. 3. Immediate blood tests: complete blood count, PT, PTT, platelet count, ESR, fibrinogen level, fasting blood sugar, cholesterol, triglyceride and blood lipids. A test for antiphospholipid antibodies (ACLA and LA) is recommended in unexplained cases of CRA occlusion. Non-invasive investigations should utilise a battery of tests: 1. Carotid non-invasive studies; the useful tests give information about the presence of a haemodynamic lesion (Dopper ultrasonography and oculoplethysmography), analyse the bruit to determine the residual lumen diameter (phonoangiography), or image the artery with ultrasound (B-Scan ultrasonography). 2. Two-dimensional echocardiogram Invasive investigations are required in selected patients: 1. A temporal artery biopsy 2. A carotid arteriogram if the patient is a candidate for endarterectomy. The patient can be screened first with a non-invasive MRA of the neck and brain. 3. A timed FFA, particularly in cases of CRA occlusion when occlusion of the ophthalmic artery is suspected, in cases of AION of possible embolic origin or in AION to document the position of the watershed zone of the choroidal circulation and its relation to the optic nerve head. Emergency treatment in CRA occlusion is designed to lower intra-ocular pressure and dislodge the embolus. In impending CRA occlusion heparin is useful. Urgent systemic corticosteroids are needed when CRA occlusion, or AION are due to arteritis. In other situations treatment is directed towards preventing recurrence or involvement of the other eye by reducing or eliminating identified risk factors.