Characterization of the microbial profile in tears of patients with primary open-angle glaucoma: results from a pilot study

This pilot study characterized the tear microbiota profile in patients with primary open-angle glaucoma (POAG) and compared it with healthy controls. Tear samples from 22 participants (10 POAG patients and 12 matched controls) were analyzed using 16 S rRNA gene sequencing. While no significant differences were found in alpha diversity, beta diversity analyses revealed distinct microbial community structures between groups, with POAG patients exhibiting a more homogeneous and less diverse microbiota. Three phyla-Fusobacteriota, Planctomycetota, and Synergistota-were significantly more abundant in the glaucoma group (p < 0.0001), and 23 bacterial genera showed differential abundance. Additionally, preserved eye drops appeared to modulate microbial composition, with specific alterations observed in several genera. These findings support the hypothesis of ocular dysbiosis associated with POAG, potentially linked to inflammatory and immunological mechanisms. The study suggests that microbiota-based interventions, such as probiotics or postbiotics, may offer complementary therapeutic strategies, and highlights the need for longitudinal studies with larger sample sizes to validate these preliminary results.