AIM:To define the ultrasonographic structure of normal lower eyelid anatomic compartments and their spacial relationship in dynamic motion.METHODS:High resolution ultrasound (15MHz) was performed on the lower eyelids of 7 normal subjects. Movements of the lower eyelid and its compartments were visualized with ultrasound. In addition, the maximal excursion area of the lower eyelid fat compartments and retractor motions was measured before and after motion.RESULTS:The orbicularis muscle could be seen as an echolucent structure between the dermis and the echodence fat pads. Lower eyelid fat pad seems to be divided into 2 compartments as range of motion and direction of movement of each of them varies. It seems that these compartments have also different behavior. The measured profile area of the visible normal lower eyelid fat pads during movement of globe from up-gaze to down-gaze decreased by 50%. Order of movement of lower eyelid structures seems to be as follows:after globe movement fist we see retractor movement, anterior orbital fat pad, then skin and septum, and finally movement of inferior fat pad.CONCLUSION: Ultrasound represents a noninvasive tool for the visualization of lower eyelid morphology. Expanding its application could help us understand the compartmental changes in physiological eyelid movement, in aging and diseased study populations, as well as assess operative outcomes.