A female client who was found unconscious at home is brought to the hospital by a rescue squad. In the intensive care unit, the nurse checks the client’s oculocephalic (doll’s eye) response by:
A. Introducing ice water into the external auditory canal.
B. Touching the cornea with a wisp of cotton.
C. Turning the client’s head suddenly while holding the eyelids open.
D. Shining a bright light into the pupil.
Correct Answer: C. Turning the client’s head suddenly while holding the eyelids open.
To elicit the oculocephalic response, which detects cranial nerve compression, the nurse turns the client’s head suddenly while holding the eyelids open. Normally, the eyes move from side to side when the head is turned; in an abnormal response, the eyes remain fixed. The oculocephalic reflex (doll’s eyes reflex) is an application of the vestibular-ocular reflex (VOR) used for neurologic examination of cranial nerves 3, 6, and 8, the reflex arc including brainstem nuclei, and overall gross brainstem function.
Option A: The nurse introduces ice water into the external auditory canal when testing the oculovestibular response; normally, the client’s eyes deviate to the side of ice water introduction. Vestibulo–ocular reflex is an involuntary reflex that stabilizes the visual field and retinal image during head motion by producing eye movements in a counter direction.
Option B: The nurse touches the client’s cornea with a wisp of cotton to elicit the corneal reflex response, which reveals brain stem function; blinking is the normal response. The corneal blink reflex is caused by a loop between the trigeminal sensory nerves and the facial motor (VII) nerve innervation of the orbicularis oculi muscles. The reflex activates when sensory stimulus contacts either free nerve endings or mechanoreceptors within the epithelium of the cornea.
Option D: Shining a bright light into the client’s pupil helps evaluate brain stem and cranial nerve III functions; normally, the pupil responds by constricting. The oculomotor nerve helps to adjust and coordinate eye position during movement. Several movements assist with this process: saccades, smooth pursuit, fixation, accommodation, vestibulo-ocular reflex, and optokinetic reflex.
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