New research examines eye microbiome differences to explain dry eyes

27 Mar 2024 --- The microbial mix in healthy eyes — part of the collective human microbiota — is different from that in dry eyes, according to new research conducted using advanced sequencing technology. These new findings could facilitate the development of novel treatments for numerous eye issues, as well as diseases in other parts of the body.

“Human microbiome research suggests a strong connection between the gut microbiome and the brain and eyes,” says Pallavi Sharma, part of the research team responsible for the study, a graduate student of Biology and a teaching assistant at the Stephen F. Austin State University in Nacogdoches, US.

“Any alteration in the gut microbiome affects other organs and can lead to disease. Therefore, we are trying to identify patterns of an imbalance between the types of microbes present in a person’s ocular microbiome for people with different health problems.”

The research team, led by Alexandra van Kley, a professor of Biology at the Stephen F. Austin State University in Nacogdoches, presented their findings at the annual meeting of the American Society for Biochemistry and Molecular Biology, held March 23–26 in Texas, US.

Microbial communities 
The researchers collected eye samples from 30 participants using a swab. The samples were analyzed through 16S rRNA sequencing and bioinformatic analysis, which allowed the team to determine the microbiome distribution for patients with healthy eyes as well as how it differs from that of people with dry eyes. 

This analysis revealed that the most common bacterial species in healthy eyes were Streptococcus and Pedobacter, while Acinetobacter were found to be most prevalent in dry eyes. 

Van Kley foresees ocular disease treatments that target the gut, the central microbiome site.“We think the metabolites produced by these bacteria are responsible for dry eye conditions,” explains Sharma. “We are performing further research to understand the metabolic pathways associated with the Acinetobacter to better understand the disease.”

 Research lead Van Kley adds: “Once we understand the eye microbiota properly, it will improve disease diagnosis at an early stage.”

“This knowledge can also serve as a catalyst for developing innovative therapies aimed at preventing and treating ocular disease as well as those that affect the central microbiome site: the gut.”

Gut-eye axis
The research team has already expressed an interest in conducting further research to explore the gut microbiome of patients living with dry eyes in order to improve understanding of how gut health affects the eye microbiota and to what extent it affects the eye microbe differences found in this study. 

Previous studies investigating the gut-eye axis have revealed a link between gut health and eye fatigue. The research revealed that consuming the postbiotic variant of Lacticaseibacillus paracasei KW3110 alleviates eye fatigue and improves overall eye health. 

Dry eye-specific investigations have shown that an increased intake of omega-3 fatty acids may support the management of dry eye symptoms. 

Dietary quality is also vital to eye health, as dark leafy greens, and yellow and orange vegetables — all rich in the plant compounds lutein and zeaxanthin — have been proven to be essential. 

By Milana Nikolova