An interdisciplinary scoping review of the emerging impact of periocular skincare products on the ocular surface microbiome and tear film stability

Background The healthy ocular surface microbiome consists of Actinobacteria , Proteobacteria , and Firmicutes phyla, with Corynebacterium , Propionibacterium , and Staphylococcus as dominant genera. This microbial environment is essential for maintaining immune homeostasis and barrier integrity. Objective To synthesize existing evidence on how periocular skincare and cosmetic products affect the ocular surface microbiome, tear film stability, and downstream ocular surface disease. Methods A systematic literature search was conducted across PubMed, Cochrane Library, Embase, Web of Science, and Scopus using Boolean MeSH term strategies. Studies from 2010 to present evaluating microbial composition of the ocular surface and the effects of exogenous exposures (cosmetics, contact lenses, medications) were included. Results Preservatives (benzalkonium chloride, parabens), surfactants, retinoids, and essential oils (tea tree oil/terpinene-4-ol) disrupt the ocular surface through non-selective microbial depletion, epithelial cytotoxicity, and lipid emulsification. These mechanisms contribute to meibomian gland dysfunction (MGD), blepharitis, and evaporative dry eye — all associated with characteristic dysbiotic microbiome shifts. Advanced sequencing technologies, including 16S rRNA gene sequencing and shotgun metagenomics, reveal taxon-level changes and functional alterations linked to inflammation and tear film instability. Conclusions Periocular product ingredients represent an underappreciated source of ocular surface dysbiosis. Regulatory gaps under current FDA and MoCRA frameworks limit ingredient-level safety evaluation. Future longitudinal studies using functional metagenomics, metabolomics, and standardized microbiome-specific testing pipelines are urgently needed.