To investigate the relationship between sleep position preference and eyebrow and eyelid position and degree of upper eyelid dermatochalasis.Methods: A prospective study evaluating the impact of sleep position on facial asymmetry was conducted at an academic ophthalmology department. Eligibility criteria included the absence of periocular-altering trauma or surgery, contact lens use, or other periorbital disease processes. Patients reported their sleep position preference on a questionnaire. Standardized digital photographs of patients were obtained, and Image J software was used for measurements and converted into millimeters based on a standard corneal limbus-to-limbus ratio. Upper and lower eyelid position, upper eyelid dermatochalasis, and eyebrow position were assessed by the following image-derived measurements: marginal reflex distance 1 (iMRD1), marginal reflex distance 2 (iMRD2), tarsal platform show (iTPS), and central brow position (iBP). These results were compared with the patient reported sleep position preference to determine correlation.Results: Seventy-one patients were enrolled and reported the following sleep position preferences: 28 (right), 24 (left), 13 (both), and 6 (supine). Patients with a right-or left-sided preference demonstrated lower iMRD1 measurements for the preferred sleep side (p < 0.0004) with no other significant difference in periorbital measurements. A larger degree of upper eyelid height (iMRD1) asymmetry was observed among patients with a sleep side preference.Conclusion: Patients with a predominant sleep side preference demonstrate a significant increase in ipsilateral upper eyelid asymmetry and an inferior upper eyelid position on the sleep side. There were no differences noted in lower eyelid position, central eyebrow position, or amount of upper eyelid dermatochalasis.