Optic neuritis

A 35-year-old female presented with a two-week history of worsening vision and pain with eye movement in the left eye (OS). She denied any other neurological symptoms, family history of multiple sclerosis, toxic exposure, recent travel or sick contacts, pets, or any history of sexually transmitted disease. The remainder of her medical history was unremarkable. On examination, her best-corrected visual acuity was 20/20 in the right eye (OD) and 20/400 OS. Pupils were equal and measured 5 mm in the dark and 3 mm in the light and there was a left relative afferent pupillary defect (RAPD). Color vision plates were 14/14 OD and 0/14 OS. Extraocular movements were full in all gaze positions. Intraocular pressure measurements and slit lamp examination were normal in both eyes (OU). Automated visual fields (Humphrey 24-2) revealed diffuse depression of the visual field OS and was normal OD (Fig. 9.1). Dilated funduscopic examination was normal OU (Fig. 9.2). Magnetic resonance imaging (MRI) of the brain and orbits with and without gadolinium and fat suppression demonstrated enhancement of the left optic nerve on T1 post-contrast images. No white matter lesions were detected on T2 fluid-attenuated inversion recovery (FLAIR) sequences (Fig. 9.3).