|What are "cotton wool spots" and what causes them? |
Cotton wool spots are small areas of yellowish white coloration in the retina. They occur because of swelling of the surface layer of the retina, which consists of nerve fibers. This swelling almost always occurs because the blood supply to that area has been impaired and in the absence of normal blood flow through the retinal vessels the nerve fibers are injured in a particular location resulting in swelling and the appearance of a "cotton wool spot. " The most common causes of cotton wool spots are diseases, which affect the retina such as diabetes and high blood pressure. Often cotton wool spots will disappear on their own, but new ones may occur because the underlying condition may continue to cause blood flow problems. Most often the cotton wool spots themselves do not cause visual difficulties, but the condition which led to the cotton wool spots can cause retinal damage and the best treatment is to address the disease that caused the cotton wool spots initially.