People often take ginkgo biloba, the most commonly used over-the-counter supplement, according to the Indiana University School of Optometry, to improve memory loss or to treat various diseases. But ginkgo can have serious side effects. The herb can increase bleeding, particularly in people who take anticoagulants or blood thinners or who are at risk for bleeding disorders. Bleeding can occur in the retina, which lines the back of the eye. Damage to the retina can impair vision. Do not take this supplement without first discussing its use with your medical practitioner.
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Ginkgo inhibits platelet aggregation and increases blood flow. Platelets, a type of blood cell, accumulate at the site of an injury to a blood vessel. Platelets, which are fragments of cells, can stick not only to injured areas but also to each other. Platelets travel along the walls of blood vessels that are lined with endothelium, which is normally smooth. When a break occurs, the fibers surrounding blood vessels attract platelets to the site, which leads to other actions that eventually halt bleeding. Ginkgo can disrupt this action, making it more difficult to stop retinal bleeding if it occurs.
Causes
Taking ginkgo can worsen retinal bleeding that occurs from other causes. Retinal bleeding can occur in people with diabetic retinopathy, high blood pressure, an increase in intracranial pressure and direct trauma to the eye. Retinal hemorrhage can occur in people with wet macular degeneration, who develop abnormal blood vessels under the macula. Anemia and low platelet count can also cause retinal hemorrhage. High altitude climbers can also develop retinal hemorrhages. The Basytr Center for Natural Health recommends ginkgo biloba to reduce nausea in mountain climbers; do not take this supplement for this purpose without your doctor's approval.
Results
Taking ginkgo could worsen the damage done by retinal hemorrhage by slowing the blood's ability to clot. The larger the hemorrhage, the more likely vision loss is to occur. Retinal detachment can develop if a large amount of blood accumulates under the retina. Severe retinal hemorrhage can irreversibly damage areas of the retina.
Prevention and Treatment
Do not take ginkgo if your doctor says you are at risk for retinal hemorrhage. While some retinal hemorrhages can be treated with laser to stop the leakage, retinal hemorrhages in the central area of vision, called the macula, cannot be fixed by laser, because laser destroys the vision in the area. A retinal hemorrhage in the macula may require frequent injections into the eye with medications that prevent growth of new abnormal blood vessels.
References
- Indiana University School of Optometry: Ginkgo Biloba
- The Eye Digest: Nutrition and Vision
- The University of Oklahoma Health Sciences Center: Platelets
- University of Michigan Kellogg Eye Center Retinal Hemorrhages
- Bastyr Center for Natural Health: Ginkgo Extract Reduces Severity of Altitude Sickness
- Optometric Management: The Many Faces of Retinal Hemorrhage
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