Pathogenesis of cotton wool patches: a clinical study.

By clinical study of fundus photographs and fluorescein angiograms, cotton wool patches (CWPs) were found in places where many nerve fibers traversed sharply demarcated border lines between perfused and nonperfused areas of the retina. The CWPs close to the disk (proximal CWPs) and those in the peripheral retina (distal CWPs) were separated and formed a bracket-like pair when the ischemic area reached a certain size. Vascular leakage was not always correlated with the CWPs. These clinical findings support the theory that impairment of axoplasmic transport plays a role in the development of CWPs.