More than 140 million people in the United States wear eyeglasses. Eyeglasses improve vision by adjusting the way the eyes bend and focus light. Ideally, light rays are refracted, or bent, as they pass through the cornea so that they focus on the retina in the back of the eye. In a healthy eye, this means that objects can be seen clearly. Most people have corneas that have a shallow or steep curvature which causes light rays to focus in front of or behind the retina. Objects may then appear blurry at certain distances or at all distances.
Glasses can correct these refractive errors. Prescriptions are measured for each eye so patients can enjoy optimal vision clarity, usually 20/20. Eyewear may be used for certain activities, such as reading for farsighted, or hyperopic patients and driving or watching television for nearsighted, or myopic patients, or may be worn at all times.
Regular eye exams test for the development and progression of refractive errors and help your doctor provide a proper prescription if eyeglasses are needed. Exams are also an invaluable tool in the early detection of eye disease.
- National Institutes of Health
- Centers for Disease Control and Prevention
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- U.S. Department of Health & Human Services
- U.S. National Library of Medicine