Optometrists (O.D.s) and ophthalmologists (M.D.s) both practice eyecare, but in different, though often overlapping, areas: In the U.S., O.D.s (Doctors of Optometry) examine eyes for both vision and health problems, prescribe eyeglasses, prescribe and fit contact lenses, and treat some eye conditions and diseases. M.D.s are medical doctors who specialize in the eyes. They examine eyes, treat disease, perform surgery, and prescribe glasses and contacts. Other non-doctor eye care practitioners include paraoptometrics, contact lens technicians and opticians. For more information on eye care practitioner training, please read the full definition.