Abstract
A complex relationship exists between human microbiota and the risk for ophthalmic disease. While the homeostatic composition of human microbiota is still being established, including what defines dysbiosis (i.e. changes in diversity and abundance), pilot research has begun to identify the potential influence of demographics, geography, and co-morbidities on the microbiota and describe their impact on ocular health. This review specifically focuses on the scientific relationships of the human oral and gut microbiota to dry eye disease (DED), a set of conditions impacting the tear film and ocular surface. Although data are sparse and often conflict across studies, the literature generally supports associations between microbial imbalance (dysbiosis) and DED and alterations in microbial diversity and abundance to specific aspects of DED. This review examines the relevant science and mechanistic relationships linking gut and oral dysbiosis and DED. Various physiochemical factors and therapeutic approaches that alter microbiota, including medications and fecal transplants are examined in relation to DED.
•The human microbiota is multi-faceted and may influence the risk for dry eye disease.•Sjogren's Syndrome and microbial dysbiosis have been associated with dry eye disease.•Dysregulated balance of pro & anti-inflammatory organisms linked to dry eye disease.•Topical hypotensives have been associated with both dysbiosis and dry eye disease.•Larger controlled studies are needed to identify microbiota mechanisms and signals.