Marcus Gunn, or Jaw Winking Syndrome

Marcus Gunn first described the syndrome in 1883. Marcus Gunn phenomenon or ‘jaw’ winking phenomenon’ is seen in 4 to 6% of congenital ptosis patients

It is believed that the nerves have strayed so the motor division of the trigeminal nerve is congenitally mixed into the superior pterygoid and the eyelid levator muscles.

Putting it in simple terms:

There is generally a congenital ptosis, where one eyelid is lower than the other.

The third and the 7th nerves are abnormally interlinked so that when a child chews it stimulates its nerve to elevate (lift/retract) the eyelid. This winking response can be triggered by opening the mouth, chewing, sucking, moving the jaw from side-to side, clenching teeth or pushing the jaw forward. This response results in the affected eye blinking and then retracting back.

It would seem the pterygoid muscle in the jaw sends a signal to ocular motor nerve to cause it to wink.

Severe cases may require corrective surgery for the ptosis. Some children will demonstrate a squint, due to a superior rectal muscle palsy. This strabismus can lead to amblopia. Any amblyopia must be treated prior to surgical intervention of the upper eyelid. 

Patients with Marcus Gunn jaw winking syndrome, should have continuous follow-up by  their eye doctor.

Runner up  X-Factor Australia artist, Taylor Henderson was also born with Marcus Gunn Jaw Winking Syndrome.

Thank you to @gracieapheonix for sharing this video with us and allowing us to share this.