Optometrists are trained and state licensed to examine, diagnose and treat eye problems. As primary-care providers, they correct and prevent visual problems by prescribing corrective lenses, contact lenses and eye exercises. Practitioners must be able to recognize signs of ocular and visual disease, as well as be able to refer patients to appropriate specialists. As they cannot perform eye surgery, patients whose vision problems cannot be corrected by an optometrist are referred to an ophthalmologist.

Optometrists may specialize in working with children, the elderly or partially sighted people who need special visual aids to improve their vision. They may concentrate on education and/or perform scientific research. Other specialized practices include contact lenses, occupational vision, pediatrics, sports vision and vision therapy.