An inflammation of the optic nerve presenting with acute vision loss and reduced color vision, with a swollen optic disc. The most likely diagnosis is:

• A. Optic Neuritis
• B. Papilledema
• C. Retinal Detachment
• D. Glaucoma

Answer: (A)

Acute inflammation of the optic nerve causes sudden vision loss with reduced color vision and often eye-pain on movement. When the nerve head is involved, the eye exam can show optic disc edema (a swollen disc), which fits this description. This presentation—acute unilateral vision loss, color desaturation, and optic disc swelling—is classic for optic neuritis, a condition often linked to demyelinating diseases like multiple sclerosis.

Papilledema would involve swelling from raised intracranial pressure and is usually bilateral with headaches and transient visual obscurations rather than a sudden loss of color vision. Retinal detachment causes a curtain-like, painless loss of vision with retinal findings on exam, not optic disc swelling. Glaucoma is typically a chronic process of optic nerve damage (or acute angle-closure with a red eye and severe pain), not a sudden central vision loss with color desaturation and disc edema.