Final answer:
The afferent limb of the corneal reflex is the sensory pathway via the trigeminal nerve, which carries the signal from the cornea to the brainstem.
Step-by-step explanation:
The afferent limb of the corneal reflex is the sensory pathway that initiates the reflex when the cornea is touched. This sensory input travels via the trigeminal nerve (cranial nerve V), which carries somatosensory information from the face to the brain. When the cornea receives a tactile stimulus, or in related reflexes, when bright light stimulates the optic nerve, the afferent limb sends a signal to the brainstem, triggering a blink response to protect the eye.