Here is a photo of a patient’s eye showing cotton wool
spots, which are the white, puffy, cloudlike tissue visualized here:
These
spots occur when there is a lack of blood supply to that area of the retina,
specifically the nerve fiber layer. Since there isn’t sufficient blood flow
through these vessels, the nerve fiber layers are injured and begin to swell and look
like puffy pieces of cotton, hence the name “cotton-wool spots.” They are most
commonly found surrounding the optic nerve and along the temporal arcades. They typically don't cause any impairment in vision, but are usually a sign of an underlying condition, such as hypertension or diabetes. They also appear in patients who have HIV.
