Effect of external eyelid weighting on eyelid and eyebrow position in normal and ptosis patients

Purpose: This study aims to characterize the physiologic response of both eyelid and eyebrow position to increasing downward forces simulated by external weights.

Methods: In this prospective observational study, both normal individuals and patients affected by ptosis were tested. External eyelid weights were placed on one upper eyelid with incrementally increasing weight from 0.2 to 2.4 g. The eyelid carrying the weight was randomly selected for normal subjects and patients with bilateral ptosis, whereas for unilateral ptosis, the ptotic eyelid was utilized. Photographs were obtained at baseline and with increasing weight until MRD1 reached 0 on the weighted side or, until 2.4 g was reached. Eyelid and brow position on the weighted and unweighted sides were digitally measured in millimeter. Primary outcome measures were change in the margin to reflex distance (MRD1) and pupil to brow distance (PTB) with weight on the weighted and unweighted sides for normal and ptosis subjects.

Results: The weighted eyelid MRD1 decreased linearly with increasing weight. This was true for normal and ptosis subjects. The unweighted eyelid MRD1 increased linearly with increasing weight. This was also the case for both normal and ptosis subjects. With increasing weight, PTB increased linearly on the weighted side. No significant intergroup differences were noted.

Conclusions: In normal and ptosis subjects, when external weight on the eyelid is incrementally increased, the weighted eyelid MRD1 decreases, the unweighted eyelid MRD1 increases, and both brows elevate in a linear fashion.