Optometry has the following meanings in the field of medicine:

1. The science that deals with assessing, diagnosing, treating, and managing the eye and related structures for visual difficulties (such as nearsightedness of farsightedness) and eye disorders (such as cataracts). Cataracts is a darkening of the lens in the eye. The lens is an organ located between the colored part of the eye, that bends light as it enters the eye.

Optometry is also concerned with vision testing, vision training, eye exercises, and the prescription of corrective devices such as eyeglasses and contact lenses, all for the purpose of making someone's vision the best it can possibly be. Someone who studies optometry is known as an optometrist.