Dazzle reflex involves which cranial nerve?

Dazzle reflex involves which cranial nerve?

• A. CN II
• B. CN III
• C. CN IV
• D. CN V

Answer: (A)

The dazzle reflex is a brainstem light reflex that relies on the retina detecting a bright flash and sending that sensory information through the optic nerve. This afferent input via the optic nerve triggers a rapid blink, with the motor output to close the eyelids carried mainly by the facial nerve. So, the cranial nerve responsible for sensing the light in this reflex is the optic nerve. The other nerves listed aren’t the primary sensory carriers for this reflex—oculomotor and trochlear nerves control eye muscles, and the trigeminal nerve is more involved in the corneal reflex—while the actual blink is driven by the facial nerve.

The dazzle reflex is a brainstem light reflex that relies on the retina detecting a bright flash and sending that sensory information through the optic nerve. This afferent input via the optic nerve triggers a rapid blink, with the motor output to close the eyelids carried mainly by the facial nerve. So, the cranial nerve responsible for sensing the light in this reflex is the optic nerve. The other nerves listed aren’t the primary sensory carriers for this reflex—oculomotor and trochlear nerves control eye muscles, and the trigeminal nerve is more involved in the corneal reflex—while the actual blink is driven by the facial nerve.