Supraclinoid aneurysm of the internal carotid artery presenting with monocular visual loss, mimicking retrobulbar neuritis

Abstract

The majority of aneurysms involving the cerebral vasculature are silent and may be found incidentally on neuroimaging. Approximately 85% of cerebral aneurysms are located in the anterior parts of the circle of Willis, especially at bifurcation sites. Unruptured intracranial aneurysms are often asymptomatic unless they enlarge and cause compression on adjacent structures. Aneurysms arising from the anterior parts of the circle of Willis, including cavernous and supraclinoid segments of the internal carotid (IC) artery or from the anterior communicating artery can compress on the anterior visual pathways, causing visual dysfunction. We hereby report the case of a 49-year-old lady, who presented with progressive loss of vision in the right eye evolving over 2 weeks; she was suspected to have retrobulbar neuritis, and on evaluation was noted to have a right supraclinoid IC aneurysm, compressing the optic nerve.