Study: Ginkgo (2003) and glaucoma

Learn more information about glaucoma treatment and information.

There has been little scientific evidence that the oral use of herbs can help glaucoma.

However, a clinical trial published in 2003 suggests that ginkgo biloba extract has possibilities.

The research looked at the effect of inkgo biloba extract on pre-existing visual field damage in normal tension glaucoma.

In normal tension glaucoma damage occurs to the optic nerve and visual field are present despite intraocular pressure measurements being 'normal'. The exact mechanisms behind the damage are unknown, but there are two primary factors:

  • reduced blood flow to the optic nerve
  • versus relatively high intraocular pressure

The researchers felt that because some patients with normal tension glaucoma can experience narrowing of the peripherial field despite conventional medical treatment, the value of other treatments is worthy of investigation. Since Ginkgo biloba has been shown to improve blood flow at a tissue level, it was an obvious candidate for selection in such investigations.

In a randomized, double-blind, placebo-controlled, crossover trial, 27 patients with bilateral visual field damage (less peripherial vision) resulting from normal tension glaucoma received Ginkgo biloba extract or a placebo. Visual field tests were performed at the beginning of the trial and at the end of each 4-week period.

The researchers measured any changes in the visual field and the development of any ocular or systemic complications. After Ginkgo biloba treatment, a significant improvement in visual field indices was recorded, but there were no significant changes found in intraocular pressure, blood pressure or heart rate.

No ocular or systemic side effects were noted in any patient during the trial. The authors concluded that Ginkgo biloba extract can improve pre-existing visual field damage in some individuals with normal tension glaucoma. However, they observed that the exact explanation is not currently understood.

Reference: Quaranta L, Bettelli S, Uva MG et al. Effect of Ginkgo biloba extract on preexisting visual field damage in normal tension glaucoma. Ophthalmology 2003; 110: 359-36