Possibly, but the science is early. Researchers have found links between the gut microbiome and eye conditions such as macular degeneration, diabetic retinopathy, glaucoma, and dry eye. Most of the evidence comes from animal studies and small human studies, so no one can yet say that changing your gut bacteria will protect your eyes.
What the Gut-Eye Axis Means
Your gut is home to trillions of bacteria, collectively called the microbiome. They help digest food, train your immune system, and produce chemicals that travel through your body. Researchers wondered whether they might also reach the eye.
One reason the idea is appealing: a French review in Experimental Eye Research points out that the retina is considered an extension of the brain, and that the gut microbiota has already been tied to brain conditions such as depression and Alzheimer’s disease, per the review. If the gut can talk to the brain, researchers reasoned, it might talk to the retina too.
A comprehensive review describes a gut-eye microbiota axis shaped by the intestinal barrier, the blood-retina barrier, and the eye’s unusual immune privilege, according to the review on PubMed Central. In plain terms, the idea is that gut bacteria influence inflammation and immune activity throughout the body, including in the retina.
Eye Conditions Under Study
The same review reports that altered microbiomes have been observed in people with retinal diseases including age-related macular degeneration and diabetic retinopathy, which suggests a gut-retina connection. Other reviews extend the list to autoimmune uveitis, glaucoma, and dry eye.
Inflammation is the common thread. A review in PubMed Central notes that inflammation underlies several age-related eye diseases and proposes that dysbiosis, a disrupted microbiome, may drive systemic inflammation that contributes to retinal disease, per this gut-eye axis review. It is an appealing theory, but a theory nonetheless.
How Strong Is the Evidence?
Honestly, it is limited. A review of the gut-eye axis described much of the support as coming largely from rodent studies, as noted in The Gut-Eye Axis: Lessons Learned from Murine Models. Mice are useful for generating ideas, but they do not always predict what happens in people.
A systematic review of clinical trials reached a similar conclusion. It found that the gut-eye axis appears to hold clinical relevance, but that current data are limited in sample size and design, and it described clinical trials targeting the microbiome as being on the horizon, per the review of clinical studies.
Association Is Not the Same as Cause
Finding different bacteria in people with eye disease does not tell us which came first. Illness, medication, diet, and age can all change the microbiome. A person with diabetic retinopathy, for example, also has diabetes, which may itself influence the gut.
That is why researchers are testing interventions, such as probiotics and fecal microbiota transplantation. The clinical-trial review searched registered studies on both, and its table includes a fecal transplant trial in people with immune-mediated dry eye. Those results will tell us far more than comparisons of bacterial profiles.
Should You Take Probiotics for Your Eyes?
There is not enough evidence to recommend a specific probiotic for eye health. Products vary widely, and the studies so far do not point to a particular strain or dose. If you take probiotics for digestive reasons, there is no reason to stop, but do not expect them to protect your vision.
If you have a condition that affects your immune system, or you are considering any supplement, speak with your doctor first.
Gut-Friendly Habits That Also Fit Eye Health
The practical advice overlaps with what is already good for your eyes. A varied diet rich in vegetables, fruit, whole grains, legumes, nuts, and fish supports your overall health, and our research summary on the Mediterranean diet and age-related macular degeneration looks at that eating pattern and AMD.
Our guides to diet for eye health and omega-3 fatty acids and eye health offer specific food ideas. Managing blood sugar also matters, so see diabetes and eye health.
What to Watch For
The gut-eye connection should not distract from proven basics. Regular eye exams catch conditions early, and no microbiome trend replaces them. Our guide to eye exams as you age explains how often to go.
It is an exciting field, and in a few years we will likely know much more. For now, treat it as a promising lead, not a treatment.
