Cotton wool spots are an abnormal finding on funduscopic exam of the retina of the eye. They appear as fluffy white patches on the retina. They are caused by damage to nerve fibers and are a result of accumulations of axoplasmic material within the nerve fiber layer. The nerve fibers are damaged by swelling in the surface layer of the retina. The cause of this swelling is due to the reduced axonal transport (and hence backlog and accumulation of intracellular products) within the nerves because of the ischemia. A 1981 analysis concluded that "in most instances, cotton-wool spots do not represent the whole area of ischaemic inner retina but merely reflect the obstruction of axoplasmic flow in axons crossing into much larger ischaemic areas". Associated findings include microvascular infarcts and hemorrhages. The appearance of cotton wool spots may decrease over time.
Diabetes and hypertension are the two most common diseases that cause these spots, and the best treatment would be to treat the underlying disease. In diabetes they are one of the hallmarks of pre-proliferative retinopathy. More rarely, HIV and Purtscher's retinopathy can also lead to the appearance of cotton wool spots.
Famous quotes containing the words cotton, wool and/or spots:
“We are constituted a good deal like chickens, which, taken from the hen, and put in a basket of cotton in the chimney-corner, will often peep till they die, nevertheless; but if you put in a book, or anything heavy, which will press down the cotton, and feel like the hen, they go to sleep directly.”
—Henry David Thoreau (1817–1862)
“After all, the wool of a black sheep is just as warm.”
—Ernest Lehman (b. 1920)
“Nobody dast blame this man.... For a salesman, there is no rock bottom to the life. He don’t put a bolt to a nut, he don’t tell you the law or give you medicine. He’s a man way out there in the blue, riding on a smile and a shoeshine. And when they start not smiling back—that’s an earthquake. And then you get yourself a couple of spots on your hat, and you’re finished. Nobody dast blame this man. A salesman is got to dream, boy. It comes with the territory.”
—Arthur Miller (b. 1915)