Superior rectus-levator synkinesis: a previously unrecognized cause of failure of ptosis surgery

Abstract

Purpose: To describe a previously unreported type of ptosis associated with abnormal synkinesis between the superior rectus muscle and the levator palpebrae superioris.

Design: Retrospective noncomparative case series.

Participants: Seven cases with congenital or longstanding unilateral ptosis presenting to a regional, tertiary referral, oculoplastic service. Six of these cases were seen within a period of 2 years.

Methods: Detailed observations of eyelid, ocular, and pupil movements of both eyes were performed before the planning of ptosis surgery anterior levator resection.

Main outcome measures: Magnitude of ptosis and its variation with the position of gaze.

Results: Ptosis present in the primary position disappeared or markedly reduced with upgaze so that measurements of levator function were apparently normal. Close examination of the relative movement of the eyelids revealed evidence of superior rectus to levator synkinesis occurring during upgaze. In three cases the synkinesis was recognized only after failed ptosis surgery. Once recognized, two of these cases underwent further surgery with an excellent result. Three other patients all had successful surgery.

Conclusions: Superior rectus to levator synkinesis may be easily overlooked if eyelid elevation in upgaze is ascribed to normal levator function rather than a synkinetic movement. We draw attention to the importance of identifying this relatively common condition to plan appropriate ptosis surgery. The lack of levator muscle tone in the primary position of gaze means that an augmented resection of the levator muscle should be performed.