Unilateral Acute Idiopathic Optic Neuritis With Superior Altitudinal Visual Field Defect as a Presenting Feature.

Patients with acute optic neuritis typically present with acute loss of vision. We describe a case of a young lady of 25 years of age with blurring of vision in the upper visual field of the right eye with otherwise intact visual acuity as the only presenting symptom. Although altitudinal visual field defect is not unknown to be associated with acute optic neuritis, it is generally considered a relatively uncommon occurrence. Our case illustrates an unusually unique occurrence of upper altitudinal visual field defect in association with unaffected visual acuity as the sole presenting symptom of acute idiopathic unilateral optic neuritis. When an altitudinal visual field defect is a presenting feature, besides the usual vascular and compressive causes, optic neuritis should be remembered in the list of differential diagnoses.