Association between ocular surface microbiota species and type 2 diabetes mellitus with or without retinopathy and related clinical parameters

being the most positively correlated with glycosylated hemoglobin A1c. Our current study revealed substantially altered OSM species profiles associated with DM/DR, suggesting a potential role for OSM species and providing new insights into the clinical correlation and diagnostic value of OSM. IMPORTANCE: . These microbial changes are linked to glycemic control, kidney function, and systemic inflammation, connecting local ocular microbiota to systemic microvascular damage. The study also highlights OSM species with strong diagnostic potential for DM and DR, indicating that noninvasive, microbiota-based biomarkers could supplement existing imaging-based screening. Overall, these findings deepen the understanding of host-microbiota interactions in diabetes and retinopathy and support future research into mechanisms, longitudinal effects, and microbiota-targeted therapies to prevent or reduce vision-threatening diabetic complications.