This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Marcus Gunn phenomenon is a rare condition characterized by movement of the upper eyelid in a rapid rising motion (a “wink”) each time the jaw moves.[1342] The wink phenomenon may be elicited by opening the mouth, thrusting the jaw to the side, jaw protrusion, chewing, smiling, or sucking.[5869] It is usually present at birth and may occur with other eye abnormalities (such as strabismus) or vision problems.[1342][5869] Although it usually affects one eye, it can affect both eyes in rare cases.[5869] The exact cause is not known. Marcus Gunn phenomenon is generally sporadic, but familial cases have been reported.[5865][5869] Treatment is not always needed but may include surgery in more severe cases.[1342]
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