What are typical features of optic neuritis?

• A. Bilateral involvement with painless vision loss
• B. Gradual peripheral vision loss without pain
• C. Rapid improvement over days
• D. Acute unilateral vision loss with eye pain, reduced color vision, and an afferent pupillary defect

Answer: (D)

Optic neuritis most often shows abrupt, one-eye (unilateral) vision loss with eye pain, especially with movement. The vision loss tends to be central rather than peripheral, and color vision is notably worse—the reds often look washed out. A key finding on exam is a relative afferent pupillary defect in the affected eye, meaning the pupil constricts less when light is shined in that eye (the swinging flashlight test highlights the defect). This combination—acute unilateral vision loss with eye pain, reduced color vision, and an afferent pupillary defect—fits the typical presentation of optic neuritis.

Bilateral painless vision loss is not characteristic; optic neuritis is usually unilateral and painful. Gradual peripheral vision loss without pain points toward other conditions such as glaucoma or retinal degenerations. Rapid improvement over days can occur, but the classic and most reliable description emphasizes the acute unilateral, painful onset with color desaturation and a relative afferent pupillary defect.