The 3 O's: Ophthalmologists, Optometrists & Opticians

We often hear about the “three O’s” in eye care: ophthalmologists, optometrists, and opticians. While only ophthalmologists attend medical school, all three professionals fulfill vital roles in the delivery of eye care.

It is easy for the public to confuse the different roles. 


The Greek root word is ophthalmos, which means "eye."

An ophthalmologist is a trained physician and surgeon who can diagnose and treat all eye diseases, perform eye surgery, and prescribe and fit eyeglasses and contact lenses to correct vision problems. Many ophthalmologists are also involved in scientific research on the causes and cures for eye diseases and vision disorders. Because they are medical doctors, ophthalmologists can recognize other health problems that aren't directly related to the eye, and refer those patients to the right medical doctors for treatment.

Every ophthalmologist first completes four years of medical school to become a medical doctor (MD), which is then followed by four years of intense internship and residency training. Many often go on to complete an additional year of fellowship training in a sub-specialty field.

Click here for more information about the extensive training that ophthalmologists complete.


Based on its root words, optometry means measurement of the eye.

An optometrist is not a physician (MD or DO).  An optometrist receives a doctor of optometry (OD) degree after completing two to four years of college-level education, which is followed by four years of optometry school.

Optometrists are licensed to practice optometry, which primarily involves performing eye exams and vision tests, prescribing and dispensing corrective lenses, detecting certain eye abnormalities, and prescribing medications for certain eye diseases. Many ophthalmologists and optometrists work together in the same offices, as a team. For instance, in Texas, optometrists may legally treat glaucoma patients in collaboration with an ophthalmologist if this arrangement is more convenient for the patient. The collaborative model works well in Texas.

Click here to see a visual representation of how the education and training of ophthalmologists and optometrists differ.


An optician is a professional who makes or sells optical instruments.

Opticians are technicians trained to design, verify and fit eyeglass lenses and framescontact lenses, and other devices to correct eyesight. They use prescriptions supplied by ophthalmologists or optometrists, but do not test vision or write prescriptions for visual correction. Opticians are not permitted to diagnose or treat eye diseases.