A PubMed search for evidence about the efficacy of the most frequently used CAM agents reveals little to no support that they provide any benefit. Although 15 articles are identified in a search for n-acetylcarnosine and glaucoma, a single individual is the author on all but 1 article, and mentions of ‘ageless vision,’ ‘powerful eye health,’ and ‘all-in-one universal antioxidant’ in the articles titles provides good reason for skepticism about the information they contain, said Dr. Welsbie.
Discussing bilberry, Dr. Welsbie explained that it is generally used as an extract from the fruit that is similar to blueberry, and the active compound is thought to be anthocyanins. The idea that bilberry has a positive effect on vision dates back to World War II where pilots in the Royal Air Force anecdotally noted ingestion of bilberry jam seemed to improve their night vision. However, results of a study enrolling young healthy men found no differences in various vision tests comparing subjects receiving bilberry and placebo-treated controls.
Results from both a retrospective study and a prospective study including patients with glaucoma show small benefits from treatment with bilberry/anthocyanins, but the data are anything but definitive.
“I would summarize the evidence by saying there is a little data in favor of bilberry use for glaucoma, but clearly more needs to be done,” Dr. Welsbie said.
He similarly concluded that there was little data to support the use of gingko biloba. Dr. Welsbie noted that this extract of the leaf from the gingko biloba tree demonstrates neuroprotective and antioxidant properties in in vitro studies and showed neuroprotectant activity in a rat model of chronic glaucoma. However, in the decade since the latter report was published, there has been no further evidence that gingko biloba is neuroprotective to retinal ganglion cells, and results from two small clinical studies enrolling patients with glaucoma produced conflicting results.
Little cause for concern