diabetic retinopathy, a disorder of retinal blood vessels. It is characterized by capillary microaneurysms, cotton-wool spots, hemorrhage, exudates, and the formation of highly permeable new vessels. The disorder occurs most frequently in patients with long-standing poorly controlled diabetes mellitus. Repeated hemorrhage may cause permanent opacity of the vitreous humor, and blindness may eventually result. Photocoagulation of damaged retinal blood vessels by a laser beam may be performed to decrease retinal ischemia and to prevent hemorrhage from the vessels.
