Cotton wool spots are small yellowish-white deposits (resembling cotton fluffs) in the retina. They represent swelling of the retinal nerve fibers. This swelling usually occurs because the blood supply to that area has been impaired and the decreased blood flow has injured the nerve fibers in that location.
The most common causes of cotton wool spots are chronic diseases, such as diabetes and high blood pressure. However, infections, trauma, toxins, and other unknown factors can also initiate the chain of events that creates the deposits.
Often cotton wool spots will disappear on their own, but some localized vision loss may be permanent.
For more information from other health sites, please visit the following webpages:
Digital Reference of Ophthalmology, Retinal Vascular Diseases
University of Michigan Kellogg Eye Center, Cotton Wool Spots
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