A new study from researchers at Karolinska Institutet suggests that a specific vitamin supplement may help slow down or even halt the progression of glaucoma, a leading cause of irreversible blindness. The findings, published in Cell Reports Medicine, have prompted a clinical trial now underway in Sweden to test the treatment in patients.
Glaucoma is a disease that gradually damages the optic nerve, usually due to increased pressure inside the eye. Over time, this damage can lead to vision loss and, in severe cases, complete blindness. Current treatments—such as eye drops, laser therapy, or surgery—aim to reduce eye pressure, but their effectiveness varies between patients.
The new research takes a different approach by targeting the metabolic health of the retina, the light-sensitive tissue at the back of the eye.
Scientists have long suspected that a substance called homocysteine, which plays a role in the body’s metabolism, might be involved in glaucoma. However, when the Karolinska team examined the effects of elevated homocysteine levels in rats with glaucoma, they found the disease did not worsen.
They also looked at glaucoma patients and discovered that high blood levels of homocysteine did not predict faster disease progression, nor was the disease more common in people genetically prone to having high homocysteine levels.
This led the researchers to conclude that homocysteine is likely a bystander, not a cause, of glaucoma.
More importantly, they found that metabolic changes in the retina—specifically, changes that impair how the retina uses certain vitamins—play a key role in the disease. These changes result in a slowed-down local metabolism in the retina, making the tissue more vulnerable to damage.
“We believe altered homocysteine levels point to a loss of vitamin-dependent metabolic activity in the retina,” said Dr. James Tribble, co-lead author of the study and assistant professor at Karolinska Institutet. “So we asked: what happens if we restore those vitamins?”
In laboratory tests, the researchers gave mice and rats with glaucoma a mix of vitamin B6, B9 (folate), B12, and choline—all nutrients known to support metabolic health. The results were remarkable:
- In mice with slowly progressing glaucoma, optic nerve damage was completely halted.
- In rats with faster-progressing glaucoma, disease progression slowed significantly.
Crucially, these results were achieved without lowering eye pressure, suggesting the vitamins work through an entirely different mechanism—by improving metabolic function in the retina rather than affecting pressure in the eye.
“The results are so promising that we’ve launched a clinical trial,” said Dr. Tribble. Recruitment is already underway at S:t Eriks Eye Hospital in Stockholm, where patients with both primary open-angle glaucoma (the most common, slower-progressing type) and pseudoexfoliation glaucoma (a more aggressive form) are being enrolled.
If successful, this treatment could mark a major shift in how glaucoma is managed—moving beyond eye pressure control to support the health of the retina and optic nerve directly.
The study highlights a growing understanding that metabolism and nutrient use in the eye play a crucial role in neurodegenerative diseases like glaucoma—and that simple, well-tolerated vitamin supplements might help protect vision.
If you care about eye health, please read studies about how vitamin B may help fight vision loss, and MIND diet may reduce risk of vision loss disease.
For more information about eye disease, please see recent studies about how to protect your eyes from glaucoma, and results showing this eye surgery may reduce dementia risk.
The research findings can be found in Cell Reports Medicine.
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