Ocular microbiome changes in dry eye disease and meibomian gland dysfunction

Area of Science:

• Ophthalmology
• Microbiology
• Genomics

Background:

• Dry eye disease (DED) and meibomian gland dysfunction (MGD) are common chronic ocular conditions associated with aging.
• The ocular surface microbiome plays a role in maintaining homeostasis, and its perturbation may contribute to disease development.

Purpose of the Study:

• To compare the conjunctival and eyelid margin microbiomes in individuals with mild to moderate DED/MGD and healthy controls.
• To investigate the impact of lacrimal dysfunction on the ocular microbiome in DED/MGD patients.

Main Methods:

• 16S rRNA gene sequencing of conjunctival and eyelid margin swabs from three cohorts (MGD, MGD with lacrimal dysfunction [MGD+LD], and controls).
• Analysis of microbial communities using bioinformatics pipelines for sequence processing, clustering (ASVs), and taxonomic classification (BCLA against GTDB 2207).

Main Results:

• Significant differences in overall microbial community composition were observed between MGD, MGD+LD, and control groups.
• DED/MGD groups exhibited greater inter-individual variability in microbial communities compared to controls.
• Reduced bacterial richness and diversity were found in females compared to males.
• Specific bacterial taxa, including Pseudomonas and Caballeronia, were more abundant in the MGD+LD group, while Corynebacterium species were elevated in the MGD group.

Conclusions:

• Ocular surface and eyelid margin microbiomes differ significantly in individuals with DED/MGD compared to controls.
• Increased abundance of certain bacteria, including lipophilic species, is associated with DED/MGD.
• Female DED/MGD patients demonstrate reduced bacterial richness and diversity on the ocular surface.