Apparently, the extract of Ginkgo biloba will reduce visual field damage in people with normal tension glaucoma.

This is a form of glaucoma where the intraocular (eye) pressure is normal, but there is optic nerve damage from some not-yet-understood source, although reduced blood flow to the region is suspect. Ginkgo extract is known to help improve blood circulation. The extract needs to be taken long term, as when the test patients were taken off the extract, the visual problems returned to the samelevel as prior.

The extract was standardized to include specific levels of ginkgo flavone glycosides and terpenes.

Source: Herbalgram #62.