The gut microbiome significantly affects digestion and, as recent studies show, systemic inflammation. Gut health has become a hot topic across medicine, with researchers racing to uncover its connections to everything from heart health to autoimmune disease. Ocular conditions are no exception.
Optometry 411 keeps you in the loop with the latest:
When gut bacteria reach the retina
An interesting recent discovery comes from an animal study on CRB1 gene mutations, which are tied to certain retinal degenerations. Researchers found that these mutations can cause both a “leaky gut” and a “leaky retina,” allowing bacteria from the gut to migrate directly to the retina. The result is inflammation that accelerates retinal damage. While these findings are preliminary (and based on animal models), they align with broader research showing that a compromised mucosal barrier can trigger systemic inflammation that affects multiple organs, including ocular tissues.
Early interventions are promising, but preliminary
A 2023 systematic review identified 25 studies linking gut dysbiosis (microbial imbalance) to ocular disease, including uveitis, glaucoma, and in some cases chalazion. Dry eye may also be influenced by gut microbiota. Only a handful of trials have tested gut-targeted treatments — like probiotics or fecal transplants — and while results were encouraging, sample sizes were small. The consensus is that the concept is promising, but we’re far from mainstream clinical protocols.
Of course, research continues to expand the picture. Other recent findings: In glaucoma, particularly primary open-angle glaucoma, certain bacterial strains and their metabolites may influence immune pathways involved in disease progression. In AMD, gut microbial profiles differ between those with advanced disease and healthy controls, suggesting a role in both inflammation and oxidative stress regulation.
In diabetic retinal disease, gut imbalance can increase intestinal permeability, allowing inflammatory molecules into circulation, which in turn can worsen retinal damage. Even retinal artery occlusion has been linked to gut changes, possibly through the same risk factors that drive vascular disease, like atherosclerosis and certain gut-derived metabolites. (source)
Systemic health links
Recent work connects the gut–eye axis to cardiovascular health. Gut microbiome imbalances may contribute to hypertension, which is a known risk factor for vision loss. Researchers are exploring whether improving gut health through diet, prebiotics, or probiotics could provide a dual benefit for vascular and ocular health.
Nutrition as a bridge between gut and eye care
For ODs looking to give patients actionable advice today, diet may be the most accessible lever. A randomized controlled trial published in The Journal of Nutrition found that eating two handfuls of pistachios daily for 12 weeks improved macular pigment optical density, likely due to lutein content, while also supporting cardiovascular and gut health.
Similarly, leafy greens like spinach and kale provide both prebiotics that feed beneficial gut bacteria and antioxidants that support retinal health. Diets high in fat and sugar have been associated with gut dysbiosis, while fiber-rich diets promote short-chain fatty acid production with anti-inflammatory benefits.
Bottom line: We’re just beginning to understand which microbes matter most, how they influence ocular tissues, and which interventions will make the biggest difference. As they say, watch this space.
Additional resources for further reading:
From Gut to Eye: Exploring the Role of Microbiome Imbalance in Ocular Diseases
The Gut Microbiome Affects Eye Disease, And May Open New Therapy Options
Gut Microbiota and Eye Diseases: A Review
This article is intended for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinicians should consult current research and clinical guidelines before applying any concepts in practice, and patients should always seek personalized advice from their healthcare provider.
