Ocular surface microbiota and its relationship with ocular surface diseases

In direct contact with the external environment, the ocular surface is susceptible to multiple antigens and pathogens.Ocular microbial communities are involved in the regulation of immune tolerance, metabolism, and epithelial barrier function.The microbial composition of the human eye plays an important role in both health maintenance and disease development.It is increasingly evident that certain diseases are caused by imbalances in the microbiota.The human microbiome is complex and primarily consists of bacteria.The human microbiome has initially been studied in five major body regions, namely, gastrointestinal tract, nasal cavity, skin, urogenital tract, and oral mucosa.The relationship between the ocular surface bacterial community and disease has become one of the hot research topics with the development of high-throughput 16SrRNA sequencing and metagenomic shotgun sequencing in the past few years.Ocular surface microbiomes differ in different regions, and they also exhibit vertical distribution characteristics.In addition, several factors, such as age, gender, environment, and geography, may affect the composition of the ocular surface bacterial community.Repeated use of topical antibiotics could lead to increased antibiotic resistance of the ocular surface bacterial community.Ocular surface diseases such as different types of dry eye, keratitis and blepharitis are related to the changes in the ocular surface bacterial community.This article reviewed the composition, distribution, and influencing factors of the ocular surface bacterial community and its relationship with dry eye, keratitis, and blepharitis, providing new insights into the mechanisms of ocular surface disease and guidance for treatment.

Microbiomics; Bacteria; Dry eye syndromes; Keratitis; Blepharitis; Ocular surface disease