Dry eye disease can be treated by oral probiotic, shows study

New York: A commercially available probiotic bacterial strain has been found to improve dry eye disease in a mouse model, according to researchers.

Dry eye is a common condition in which tears produced by the eye can't keep the eye adequately lubricated.

It can cause eye stinging and burning, inflammation, blurry vision and light sensitivity. Extreme cases can result in damage to the eye's surface if left untreated.

The most common treatments involve the application of eye drops, gels or ointment. This new, unconventional treatment involves bacteria in the intestinal tract.

"The 'friendly' bacteria that live in the human gastrointestinal tract have been linked to health and protection against disease in many parts of the body, including the gut, brain and lung," said Laura Schaefer, from Baylor College of Medicine in Texas, US.

"It's therefore not surprising that the gut microbiome also has effects on our eyes," she added.

Schaefer presented the findings at ASM Microbe 2023, the annual meeting of the American Society for Microbiology.

In the study, the team used an orally administered probiotic bacterial strain - Limosilactobacillus reuteri DSM17938 - in a dry-eye mouse model.

DSM17938 is a human-derived, commercially available probiotic bacterial strain that has already demonstrated protective effects in the gut and immune system in humans and mice, but it has not been tested in the context of eye health.

Mice were first treated with antibiotics, which kills many of the "friendly" bacteria living in the gut. They were then exposed to very dry conditions and fed daily doses of either probiotic bacteria or a saline solution as a control. After five days, the eyes were examined for disease.

The mice that were fed the probiotic bacteria had healthier and more intact corneal surfaces. In addition, these mice had more goblet cells in their eye tissue, which are specialised cells that produce mucin, an essential component in tears.

Taken together these data suggest that the right oral probiotic could help treat and manage dry eye symptoms, the researchers said.