Glossary of Common Eye Problems

• Cataract: The most frequent cause of preventable blindness in the world, a cataract is a clouding of the lens of the eye, which is normally transparent. Last year more than 1.3 million cataract operations were performed in the U.S.
• Corneal Disease: The cornea is the clear front surface of the eye, which can become clouded, distorted or scarred by injury, disease or hereditary defects.
• Diabetic Retinopathy: This condition occurs in diabetics when the blood vessels that nourish the retina leak and cause scar tissue to form. It is the leading cause of blindness among working-aged Americans. For more information, visit the American Diabetes Association Web Site.
• Glaucoma: In glaucoma, the build-up of fluid pressure within the eye damages the optic nerve. The most common form, chronic open-angle glaucoma, initially causes the loss of peripheral vision, usually without any associated pain or discomfort. Acute angle-closure glaucoma, a rarer form, develops suddenly, is accompanied by intense pain, and causes blindness within a day or two if left untreated. For more information, visit The Glaucoma Foundation.
• Macular Degeneration: The macula is a tiny area of the retina that allows clear central vision such as that needed to read or drive. A deterioration of the macula known as age-related macular degeneration (ARMD) is a leading cause of blindness in Americans over 65 years of age.
• Retinitis Pigmentosa (RP): A family of inherited diseases, RP causes deterioration of the retina resulting in night blindness, tunnel vision and loss of sight. More RP resources are available on the Retinitis Pigmentosa page of the Low Vision Gateway web site.
• Strabismus: Strabismus (crossed eyes) is a major cause of amblyopia (lazy eye). It occurs when one or both eyes fail to develop normal sight during childhood. Without corrective treatment, the disorders lead to significant visual loss and diminished depth perception.
• Uveitis: An inflammation of the uvea, the middle layer of tissue behind the white of the eye, the condition can be sight-threatening and results in about 10 percent of the blindness that occurs in the U.S. The cause of uveitis is poorly understood, but a variety of systemic diseases are associated with it.