Levator function revisited: a two-phase assessment of lid movement to better identify levator-superior rectus synkinesis.

Abstract

To assess a two-phase method of recording levator function in order to facilitate the identification of patients with ptosis who have a synkinesis between the levator and superior rectus muscles. 40 consecutive patients who attended oculoplastic clinics with ptosis and 22 patients with normal lid function were recruited. In each subject, levator function was recorded by the conventional method, measuring total upper eyelid excursion between the extremes of down-gaze and up-gaze. Levator function was also assessed using our novel two-phase approach in which upper-eyelid excursion is measured separately between down-gaze and primary position (Phase 1), and between primary position and up-gaze (Phase 2). In normal patients and most of the patients with ptosis, the majority of lid movement and hence levator function occurs between down-gaze and the primary position (Phase1). In those patients with ptosis and levator-superior rectus synkinesis, a higher proportion of lid movement occurred on up-gaze (Phase2). The two-phase measurement of lid movement highlights levator function in differing gaze positions and facilitates the identification of those patients with levator-superior rectus synkinesis.