PURPOSE:Age-related change in ocular appearance occurs throughout adulthood, and involutional alterations in periocular tissues are common in middle-aged or older adults. This study sought to investigate significant differences in periocular anthropometry between young and middle-aged adults of Chinese Han ethnic group. METHODS:A total of 589 Chinese Han adults were recruited for cross-sectional investigation: 309 young adults (20 to 30 years), and 280 middle adulthood (50 to 70 years). Standardized, frontal view photographs were taken from each subject for measurements of 17 ocular anthropometric parameters (11 linear, three angular and three indicial parameters) detailing dimensions of palpebral fissures, and eyebrows. Eyelid crease morphologies were also evaluated. FINDINGS:Distribution of eyelid crease subtypes were different between the two age-groups, and an eyelid subtype (Type VI Closed Crescent) was uniquely found in middle-aged adults. Significant differences were found in majority of the ocular parameters. For most of the fissure-related measurements, values were greater in young adults. For some distance-dimensions between eyes and eyebrows, values were greater in the middle-aged adults. Detailed evaluation of periocular parameters of different age was individually performed for two subjects, which embodied findings from the cross-sectional analysis. CONCLUSIONS:By comparison of anthropometries between age-groups, we found alterations in periocular and eyelid morphologies under effect of aging, with association of laxity and loss of elasticity in periocular tissues. This study was the first to provide normative periocular dimensions of early and middle adulthoods in Chinese Han, which is useful for considerations in esthetic surgical decision-making for this population.