Extensive unilateral visual field loss due to peripapillary arteriovenous malformation.

We report on a case of extensive unilateral visual field loss due to a peripapillary arteriovenous communication. Interventional case report. A 27-year-old Caucasian woman who was initially managed for retrobulbar optic neuritis underwent fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) 6 months later that revealed an unusual course of the central retinal vein with focal dilatation and co-existent aneurysmal distention of the adjacent large choroidal vein. Subsequent colour Doppler flow imaging of the dilated area confirmed the existence of arterial flow suggesting a "vascular steal" phenomenon resulting in choroidal and optic disc ischaemia. Brain magnetic resonance imaging (MRI) revealed small focal capillary vessel abnormalities in the parietal cortex. The present case highlights the important role of ICGA and FFA in the assessment of patients with optic disc pallor and visual field loss. In our case an unusual ocular vascular abnormality was attributed to a congenital malformation and therefore an unnecessary therapeutic intervention was avoided.