Dynamic Measurement and Analysis of Upper Eyelid Changes Using Ultrasound Biomicroscopy.

Purpose: To define the regular upper eyelid anatomy and their changes during dynamic motion using ultrasonographically depicted structures.

Design: A cross-sectional study.

Methods: High-resolution ultrasound biomicroscopy (50MHz) was performed on 84 upper eyelids of 42 healthy volunteers without evidence of eyelid conditions. The skin-orbicularis oculi complex (SOOC), levator aponeurosis, and Müller's muscle-conjunctival complex were imaged. The thickness of these structures was measured in primary gaze and downgaze positions.

Results: SOOC and levator aponeurosis thickness was bigger with eyes open than with eyes closed (p < 0.01). With eyes closed, the thickness of SOOC on the pupillary midline and levator aponeurosis was positively correlated with age (p < 0.05, p < 0.01, respectively), and the thickness of levator aponeurosis and SOOC on the pupil midline was also positively correlated with BMI index (p < 0.05). Similarly, SOOC thickness on the medial and lateral canthus line is also positively correlated with BMI index and age (p < 0.05, p < 0.01, respectively). As for the differences between genders, the mean thickness of SOOC and levator aponeurosis was statistically different (p < 0.05, respectively). The magnitude of levator aponeurosis thickness in men varied more than in women in different ocular positions (p < 0.05). All measurements had an intramethod between 0.624 and 0.792, and inter-rater ICC and intrarater ICC between 0.748 and 0.850.

Conclusions: Ultrasound biomicroscopy represents a noninvasive tool for the visualization of upper eyelid morphology. Expanding its application can help to understand the dynamics of upper eyelid physiological movement, aging, and disease research in different populations and evaluate surgical outcomes.