Eye Disease Definitions

Common terms — symptoms, tests, treatments, surgery, diseases & conditions, anatomy — eye doctors use. These definitions may help you understand them better. The information given is for information purposes only and is not intended to replace professional medical advice from your physician, or to diagnose or treat a health problem or disease.

Anatomy of the Eye

The ability to see is dependent on the actions of several structures in and around the eyeball. The graphic below lists many of the essential components of the eye’s optical system.

Low Vision Defined

Low vision means that even with regular glasses, contact lenses, medicine, or surgery, people find everyday tasks difficult to do. Reading the mail, shopping, cooking, seeing the TV, and writing can seem challenging. Millions of Americans lose some of their vision every year. Irreversible vision loss is most common among people over age 65.

Vision Problems in the U.S.

Vision Loss from Eye Diseases Will Increase as Americans Age With the aging of the population, the number of Americans with major eye diseases is increasing, and vision loss is becoming a major public health problem. By the year 2020, the number of people who are blind or have low vision is projected to increase substantially. These findings appear in the April issue of Archives of Ophthalmology.