In cranial nerve VI palsy, which statement best describes the typical presentation?

• A. Bilateral ptosis
• B. Dilated pupil with eye deviation
• C. Inability to abduct the affected eye with horizontal diplopia
• D. Loss of color vision

Answer: (C)

A cranial nerve VI palsy mainly disrupts the lateral rectus muscle, which normally abducts the eye. When that muscle is weakened or paralyzed, the eye drifts inward (adducts) and the person experiences horizontal double vision that is worse when looking toward the affected side. The diplopia is horizontal because the vertical alignment stays relatively intact. The pupil and its parasympathetic function are not affected by a VI nerve problem, so you don’t see a dilated pupil. Ptosis points more toward a third nerve issue, and loss of color vision would imply optic nerve involvement, not a sixth nerve problem.