Every one of us harbors microorganisms on our ocular surfaces—part of the body’s so-called “microbiome” that’s part of a complex relationship that impacts eye health. Researchers recently discovered a core set of microorganisms shared by more than 75% of their study participants: Enhydrobacter, Brevibacterium, Staphylococcus, Streptococcus and Cutibacterium.

But they also discovered significant differences in the microbiota of those with aqueous deficient dry eye disease (DED), suggesting these microorganisms, or their absence, play a part in DED pathophysiology.

The team studied conjunctival swab samples from patients aqueous deficient DED (18 with ocular graft-vs.-host disease, 21 without) and 28 controls. They isolated the bacterial DNA from the swabs and analyzed them with gene sequencing.

They found those with DED not only had decreased microbiota diversity, but a different composition than controls. While Pseudomonas was a biomarker for controls, Bacilli was the biomarker for those with aqueous deficient DED.