Degenerative and Other
Diseases A major cause of visual loss in the United States and Europe is cataract, an opacity
of the lens most frequently associated with aging or certain metabolic
diseases. Recent evidence has linked some forms of cataracts with defective genes. A cataract can be removed surgically. Another common eye disease is glaucoma, an elevation of the pressure inside the eye. This disease can be treated with drugs or surgery, including laser surgery.
Diabetic retinopathy is a vascular disease of the retina associated with diabetes. It is possible to halt or reverse this disease by the use of laser coagulation of the retina. Macular degeneration, a condition that affects the central retina, is a common cause of visual loss in the elderly. Retinal
detachment is a condition in which the retina separates from the underlying layers. About 1 in 10,000 persons suffers a detached retina, with the highest incidence occurring in people who are severely nearsighted; 1 in 50 develops a retinal detachment after successful cataract surgery. Premature infants are at risk of developing retinopathy of prematurity, which can lead to retinal detachment and partial or total blindness. Laser application or freezing treatments to certain parts of the retina in some of these infants can reduce the risk of blindness.
Retinitis pigmentosa is a genetic disorder. Its first symptom is decreased night vision, and it may be associated with hearing loss and a variety of metabolic diseases. The leading cause of visual impairment in children is a vitamin-A deficiency, which occurs mainly in developing countries and leads to corneal degeneration and impairment of night vision.
The most common cancer of the eye is retinoblastoma in children and uveal melanoma in adults. Treatment depends on the extent of the tumor, and ranges from localized freezing, laser or radiation treatment, or removal of the affected eye.