Marcus Gunn jaw-winking phenomenon: a new supplemental test in the preoperative evaluation.

PURPOSE: To introduce a new method for the evaluation of Marcus Gunn jaw-winking ptosis that more precisely defines the severity of blepharoptosis.

METHODS: A retrospective review of 16 consecutive patients with Marcus Gunn jaw-winking ptosis presenting to our institution between 1993 to 1999 was performed. The position of the affected eyelid was observed after applying a technique of jaw immobilization and disruption of fusion with temporary occlusion of the ipsilateral side.

RESULTS: In patients presenting with mild to moderate Marcus Gunn jaw-winking, the majority (62.5%) demonstrated a positive test, uncovering complete or near complete ptosis. Test results were partially positive in 3 patients (18.8%) with increased but not complete ptosis and negative in 3 patients (18.8%) with no change in eyelid position.

CONCLUSIONS: Blepharoptosis associated with Marcus Gunn jaw-winking phenomenon is often more severe than found by conventional clinical evaluation. This finding may explain the frequent undercorrection and unpredictable results following levator resection. In patients exhibiting a positive jaw-winking ptosis test, disappointing outcomes with levator resection may be avoided by instead proceeding with a frontalis suspension with levator disinsertion as recommended for ptosis with severe jaw winking.