Source: User’s Guide to Nutritional Supplements, Jack Challem, Editor
Diabetic retinopathy is a serious complication of diabetes that damages the small blood vessels of the retina. People with diabetes are at increased risk of developing eye problems such as cataracts and glaucoma, but diabetic retinopathy is the number one vision threat for diabetic patients, affecting half of all diabetics in America. If left untreated, about half of those with the advanced form, proliferative retinopathy, will become blind within five years, compared to just 5 percent of those who receive treatment.
In the early stages of the disease – called non-proliferative, or background retinopathy – the small blood vessels of the retina weaken and develop bulges (micro-aneurysms) that can leak blood (hemorrhage) or fluid (exudates) into the surrounding tissues. The person’s vision is rarely affected during this stage of retinopathy.
In the advanced, proliferative stage of retinopathy, circulation problems resulting from damaged and narrowed blood vessels cause the retina to become oxygen-deprived. To cope with this, the circulatory system attempts to maintain adequate oxygen levels within the retina by forming fragile new blood vessels that can grow on the retina and extend into the vitreous (the jellylike substance inside the back of the eye).
These fragile vessels can rupture and release blood into the interior of the eye, leading to blurred vision or temporary blindness. The resulting formation of scar tissue here can eventually pull the retina away from the back of the eye (retinal detachment), and lead to permanent vision loss.
Ginkgo and Retinopathy
A number of experimental studies suggest that ginkgo extracts are potentially useful for treating retinal damage induced by a variety of disorders. Many of the results point to antioxidants as the reason for the protective effects of the extract. In addition, it is suspected that ginkgo’s ability to inhibit the platelet-activating factor (PAF), is involved in protecting eye tissues from retinopathy.
Antioxidants and Retinopathy
Antioxidants have been shown to prevent the oxidative damage that causes retinopathy. Vitamin C also strengthens the capillaries that supply blood to the retina. Vitamin C and other antioxidants, such as vitamin E and selenium, have been shown to reduce the damaging effects of retinopathy. Doses of 500-2,000 mg per day have been used for this condition.