An optometrist is an eye doctor who has earned the Doctor of Optometry (OD) degree. Optometrists examine eyes for both vision and health problems, and correct refractive errors by prescribing eyeglasses and contact lenses. Optometrists are trained to diagnose and treat most eye problems and diseases. An ophthalmologist is a medical doctor (MD) or a doctor of osteopathic medicine (DO) who specializes in eye and vision care. Ophthalmologists are trained to perform eye exams, diagnose and treat disease, prescribe medications and perform eye surgery.