 Glaucoma is now the leading cause of irreversible vision loss in the world. It's caused by the deterioration of the optic nerve that connects the eye to the brain. Most commonly this is due to excessive pressure inside the eyeball. Ginko biloba is one of the most common supplements taken by glaucoma sufferers. It doesn't seem to lower intraocular pressure, but MRI studies suggest ginko supplements may increase cerebral blood flow in the brain. What about blood flow to the eyes? Ginko increases ocular blood flow in both normal and glaucoma subjects, so it was put to the test. Compared to sugar pills, 40 mg of a ginko extract twice a day on top of their regular anti-glaucoma medications appeared to significantly slow the progression of visual defects in open-angle glaucoma patients. The most common type, though it's not clear in this study if the participants were properly randomized. Aside from a single-published case report of visual improvements after ginko supplementation, there don't appear to be any other studies on open-angle glaucoma, but there have been two interventional trials on the less common normal tension type. They were both randomized, double-blind to the sebo-controlled crossover trials using the same dose and duration. One found a significant benefit in improvement in pre-existing visual field damage, but the other found no benefit at all. If you want to try it despite the underwhelming results, make sure to first discuss with your healthcare professional due to a possible increase in bleeding risk from the herb. Any other supplement possibilities? In 2017, extraordinary results were reported in a leading scientific journal, Nicotinamide, a form of vitamin B3, was able to prevent the development of glaucoma in aged mice prone to the disease with more than 90% effectiveness. Watered or severe nerve damage, it was found in about two-thirds of the control mice, but 93% of the mice given nicotinamide had none. The researchers concluded the degree of protection afforded by administering the single molecule is unprecedented and unanticipated. A commentary on the study, published in the New England Journal of Medicine, entitled, Nicking Glaucoma with Nicotinamide, suggested clinical trials should be initiated. The researchers thought to give it a try, based on the fact that glaucoma in its mice had a comparable deficiency in NAD+, from which nicotinamide is a precursor. Is that even the case in people? Apparently so. Those with glaucoma have about a third lower nicotinamide levels in their blood compared to age-matched peers, and greater intake of niacin, which is another form of B3, is associated with less glaucoma. It was time to put it to the test, and the title gives it away. In 2020, an international team of researchers published a study in which glaucoma patients were randomized to nicotinamide or placebo for 12 weeks and then switched for another 12 weeks, and significantly fewer patients suffered further visual field deterioration while on the nicotinamide, 4% versus 12% while on placebo. A 2022 study found significant improvements in visual function compared to placebo within two months, but it's not directly comparable since they also added pyruvate, which is another component of energy metabolism, for discussion of cost, labeling confusion, and potential side effects of taking nicotinamide. Check out the NAD chapter in my book, How Not to Age, which I go through the pros and cons of all nine NAD-boosting supplements. It's like a tongue twister. N-A-N-A-M-N-M-N-R-N-A-N-D-A-D-H-N-M-N-H-N-R-H trip to fan. Or you just stay tuned here on NutritionFacts.org for an upcoming series of videos on the subject.