The oculocardiac reflex is a brainstem reflex that causes a decrease in heart rate during traction on the extraocular muscles (1). This reflex protects the retina from potential damage during eye movement by coordinating the actions of the oculomotor and vagus nerves (2).

When the eye is moved by applying pressure on the globe, this traction stimulates proprioceptive receptors in the extraocular muscles. Sensory information is then transmitted via the ophthalmic division of the trigeminal nerve (CN V) to the trigeminal nucleus in the brainstem (3). Interneurons relay these proprioceptive signals to the vagal nucleus, which responds by decreasing cardiac output and heart rate via the vagus nerve – the efferent limb of the reflex (4).

The oculocardiac reflex is enhanced by stimulation of the carotid sinus, anesthetic agents, and increased intracranial pressure (5). It is diminished by anticholinergics like atropine, bilateral vagotomy, and in patients with diabetes mellitus (6). This reflex helps prevent jerking movements of the eye from damaging the delicate retina during ocular surgery.