The doll's eyes reflex tests the function of which cranial nerve?

• A. Cranial nerve II
• B. Cranial nerve V
• C. Cranial nerve VII
• D. Cranial nerve III

Answer: (D)

The doll's eyes reflex, or oculocephalic reflex, tests the brainstem’s ability to coordinate eye movements in response to head motion. When the head is turned, the eyes should move in the opposite direction to preserve gaze. This movement relies on the ocular motor pathways that drive most of the extraocular muscles, which are controlled by the oculomotor nerve. If this nerve is intact, the eyes will continue to move appropriately with head rotation; if the oculomotor nerve is impaired, the eyes may not move normally with the head. The other nerves listed don’t govern the eye movements required for this reflex: the optic nerve handles vision, the trigeminal nerve handles facial sensation and chewing, and the facial nerve controls facial muscles.