Which of the following etiologies of optic nerve edema is LEAST likely to affect visual acuity?

• A. NAION
• B. Diabetic papillopathy
• C. Optic neuritis
• D. AAION

Answer: (B)

Optic nerve edema shows varying impact on vision depending on the underlying process. Ischemic (such as non-arteritic and arteritic) optic neuropathies injure the optic nerve head quickly, so they typically produce sudden, pronounced loss of visual acuity. Inflammatory optic neuritis also commonly reduces acuity during the active phase because demyelination disrupts signal transmission.

Diabetic papillopathy stands out because it involves mild, often self-limited edema of the optic disc in diabetics, with the axons relatively spared. Visual acuity is usually preserved or only minimally affected, and recovery is common as the edema resolves. This preservation of function is why diabetic papillopathy is the least likely among these etiologies to impair visual acuity.