The Influence of Age and Sex on Ocular Surface Microbiota in Healthy Adults

Purpose: A growing body of evidence suggests that the microbiome of the ocular surface confers potent immunoregulatory functions and has a key role in the physiologic maintenance of healthy eyes and in the pathogenesis of ocular diseases. Although the microbiome is known to be affected by age and sex, the influence of these factors on ocular surface microbiota in healthy adults remains largely unknown. Methods: Ocular surface microbiome samples were obtained from the inferior bulbar conjunctiva of 48 young and 42 old adults at Zhongshan Ophthalmic Center. Using metagenomic shotgun sequencing, we characterized the sex- and age-differences in conjunctival microbiome profiles of healthy adults. Results: Male and female groups differed only in the β diversity of bacterial communities, while there were significant differences in bacterial composition, metabolic functions, and the abundance of antibiotic resistance genes between young and old adult groups. Conclusions: Our findings suggest that age and sex collectively shape the conjunctival microbiome, and may change the immune homeostasis of the ocular surface through alterations of its commensal microbiome.