From Health to Disease: A Comprehensive Review of Ocular Surface Microbiota and Detection Methods in Dry Eye

Dry eye disease (DED) is a prevalent and multifactorial condition that significantly impacts the ocular surface, characterized by symptoms of discomfort, visual disturbance, and tear film instability. Recent research has increasingly focused on the ocular surface microbiome (OSM) and its potential role in the pathogenesis and progression of DED. The OSM consists of a diverse community of microorganisms, including bacteria, fungi, and viruses, that interact with the host to maintain ocular surface health. Dysbiosis, or the imbalance of these microbial communities, has been linked to various ocular surface disorders, including DED. This review comprehensively summarizes the current understanding of the differences in OSM between healthy individuals and patients with different types of DED, such as aqueous-deficient dry eye, evaporative dry eye, and DED associated with autoimmune conditions. Additionally, it explores the detection methods used to study the OSM, highlighting the strengths and limitations of culture-based approaches, 16 S rRNA sequencing, metagenomic shotgun sequencing, and emerging technologies like 2bRAD-M. The review also outlines future research directions, emphasizing the need for advanced multi-omics approaches, personalized microbiome-based therapies, and longitudinal studies to further elucidate the role of the OSM in DED. By enhancing our understanding of the OSM composition and function, these insights may lead to innovative diagnostic and therapeutic strategies for managing DED.