Trigeminal Neuropathy with Loss of the Corneal Reflex

This is a woman who underwent radiofrequency ablation for left trigeminal neuralgia. Examination demonstrated loss of facial sensation on the left in addition to an absent corneal reflex on the left, consistent with involvement of the V1 (ophthalmic) branch of the trigeminal nerve. When the cornea is touched with the tissue on the right side, both eyelids close - it is thought that trigeminal afferents (resulting from stimulation of the cornea) reach the superior colliculus (SC), which projects to and activates the bilateral orbicularis oculi subnuclei (within the facial motor nucleus), causing a reflexive blink. (The SC plays a significant role in the coordination of muscles involved in blinking by also projecting to the central caudal nucleus, which innervates bilateral levator palpebrae muscles via the oculomotor nerves.) When the left corneal is stimulated, there is no response on either side as the afferent limb of the blink reflex is abolished. [[Number of Videos and legend for each: 1, patient with a normal corneal reflex on the right and absent reflex on the left.]]