Many available natural compounds used as non-pharmaceutical therapy have been reported to show beneficial effects on circulation, the immune system and neuroprotective activities. The mechanism of action of neuroprotection most common to natural compounds is antioxidant/free radical scavenging activity. However, many other actions are present and some extracts, such as Ginkgo biloba and curcumin, have widespread activity on a number of enzyme systems. There has been a paucity of clinical trials examining neuroprotective effects of these compounds on ocular diseases. More are warranted.
Among natural compounds and extracts of great interest for glaucoma are curcumin, omega-3 fatty acids and Ginkgo biloba. Curcumin, a component of the commonly used spice, turmeric, is a potential neuroprotective candidate for glaucoma.Curcumin studies have increased greatly in recent years, with over 2000 papers published since 2000. Curcumin has shown possible beneficial effects in most of the mechanisms thought to be involved in the development and progression of glaucoma. A pilot study has shown that it slows disease progression. A clinical trial on patients with glaucoma is on the horizon.
Omega-3 fatty acids, found most notably in fish oil, play an important role in reducing oxidative damage in the retina, improving ocular blood flow and protecting against retinal ischemia (decrease in the blood supply) induced by increased IOP. While studies have not specifically addressed glaucoma, it has been suggested that fish oil may reduce IOP and be relevant to glaucoma because of its protective effect on the macula and its benefits for other eye problems.
Ginkgo biloba extracthas been claimed effective in the treatment of a variety of disorders associated with aging. It appears to have many qualities applicable to the treatment of non-IOP-dependent risk factors for glaucomatous damage. It is believed to improve central and peripheral blood flow, reduce spasm of the blood vessels, and have protective effects against free radicals because of its antioxidant property. It has been shown to be effective in treating Raynaud’s disease, which is strongly associated with normal-tension glaucoma. These and other properties raise the possibility that this herb may be a potential antiglaucoma therapy.