Effects of Age, Gender and Laterality on the sEMG of the Orbicularis Oculi in Healthy Adults.

: The orbicularis oculi muscle (OOM) is crucial for eyelid function and ocular protection. Surface electromyography (sEMG) is a useful tool for assessing OOM activity, but interpretation remains limited due to a lack of standardized reference values. This study investigates the influence of gender, laterality, and age on OOM activity using sEMG. : In total, 84 healthy adult participants (44 females and 40 males) underwent sEMG measurements for both eyes during gentle (GEC) and maximal (MVC) voluntary eyelid closure. : The average age was 62.5 years (ranging from 27 to 86; SD = 13.79) for males, and 63.12 years (ranging from 27 to 87; SD = 13.8) for females. The mean Root Mean Square (RMS) MVC values were 157.80 ± 56.43 for men and 146.45 ± 56.48 for women. The mean RMS GEC values were 7.42 ± 2.94 for men and 8.35 ± 4.86 for female. No significant gender-based differences were found (-value = 0.195 and 0.138, respectively). No significant differences between sides were found: The mean RMS MVC values were 152.24 ± 57.73 for left eyes and 151.47 ± 55.74 for right eyes (-value = 0.93). The mean RMS GEC values were 8.29 ± 5.04 for left eyes and 7.53 ± 2.79 for right eyes (-value = 0.227). The age of participants correlated negatively with maximal amplitude, mean amplitude, RMS and the difference between RMS and RMS baseline in MVC (-value < 0.001). : While OOM function remains consistent across gender and between eyes, aging contributes to a decline in OOM performance. Age-adjusted reference values may be beneficial in clinical and research applications assessing facial muscle function.