An O.D. is a Doctor of Optometry, a healthcare provider who specializes in eye and vision care. The “O.D.” stands for the Latin “Oculus Doctor,” and it’s the professional degree earned after four years of optometry school. O.D.s examine eyes, diagnose and treat eye conditions, prescribe glasses and contact lenses, and manage certain eye diseases with medication. They are not the same as ophthalmologists (M.D.s who perform eye surgery) or opticians (who fit and sell glasses).
Education and Training
Becoming an O.D. requires significant schooling. Most applicants complete a four-year bachelor’s degree in a science field like biology, though the minimum requirement is three years of undergraduate education. After that, O.D. programs take four years to complete, meaning most optometrists spend eight years in higher education before they begin practicing.
After earning the degree, optometrists must pass a multi-part national board exam administered by the National Board of Examiners in Optometry. The exam has three main parts plus an additional clinical component, all of which must be passed before a state will grant a license. Some O.D.s also complete an optional one-year residency to specialize in areas like ocular disease, cornea and contact lenses, or primary care.
What an O.D. Does in Practice
The core of an optometrist’s work involves examining eyes for vision problems and prescribing corrective lenses. But their role goes well beyond reading an eye chart. O.D.s diagnose and treat conditions like glaucoma, dry eye, conjunctivitis, and diabetic eye disease. They can remove foreign objects from the cornea, insert punctal plugs to treat dry eye, and manage infections with prescription medications.
In most states, optometrists prescribe topical eye medications including antibiotics, antivirals, anti-inflammatory drops, and glaucoma medications. Many can also prescribe certain oral medications: a 10-day course of oral antibiotics, a short supply of oral antihistamines, nonsteroidal anti-inflammatory drugs, and in some cases mild pain medications.
One thing that surprises many people is how much a routine eye exam can reveal about overall health. The retina is one of the only places in the body where blood vessels can be observed directly without surgery. Through that window, an O.D. can spot early signs of diabetes (from leaking blood vessels in the retina), high blood pressure (from unusual kinks or bleeding in retinal vessels), high cholesterol (from a yellowish ring around the cornea), and even brain tumors (from swelling near the optic nerve). Eye exams have also caught early signs of multiple sclerosis, thyroid disease, lupus, stroke risk, and certain cancers. These findings often show up before a person has any other symptoms.
Laser and Surgical Procedures
Historically, optometrists did not perform surgery. That line has blurred considerably. As of 2025, more than a dozen U.S. states allow O.D.s to perform certain laser procedures. Oklahoma was one of the earliest, granting laser privileges in 1998. States like Colorado, Virginia, Louisiana, Wyoming, and others have followed, typically allowing procedures such as YAG laser capsulotomy (used to clear cloudy vision after cataract surgery), selective laser trabeculoplasty for glaucoma, and laser peripheral iridotomy.
Several of these states also permit optometrists to perform injections, remove skin tags around the eye, and treat chalazia (small eyelid bumps) with steroid injections. The specific procedures allowed vary significantly by state, so what your optometrist can do depends partly on where you live. Major refractive surgeries like LASIK and PRK remain almost exclusively in the hands of ophthalmologists.
How O.D.s Differ From Ophthalmologists
This is the distinction most people are trying to sort out. An ophthalmologist holds a medical degree (M.D. or D.O.) and completes a surgical residency. Their training includes preoperative evaluation, surgical technique, anesthesia considerations, and managing complications during and after surgery. An O.D.’s training is focused on eye exams, vision correction, screening, and nonsurgical disease management.
In practical terms, if you need a routine eye exam, a glasses prescription, treatment for pink eye, or ongoing management of early glaucoma, an O.D. handles all of that. If you need cataract surgery, retinal detachment repair, or LASIK, you’ll see an ophthalmologist. Many people see an optometrist as their primary eye care provider and only visit an ophthalmologist if a surgical or complex medical issue arises. The two often work together, with O.D.s referring patients to ophthalmologists when needed.
How O.D.s Differ From Opticians
Opticians are not doctors. They don’t examine eyes, diagnose conditions, or prescribe medication. Their role is to take the prescription an O.D. or ophthalmologist writes and help you choose the right frames and lenses, ensure a proper fit, and make adjustments. Think of the optician as the person behind the counter at the glasses shop. The O.D. is the one in the exam room determining what prescription you need and checking your eyes for disease.
When You’d See an O.D.
For most people, an optometrist is the right starting point for eye care. Common reasons to schedule a visit include blurry vision, eye strain, headaches related to vision, red or irritated eyes, floaters, and routine annual exams. The American Optometric Association recommends comprehensive eye exams every one to two years for most adults, with more frequent visits for people over 60, those with diabetes, or anyone with a family history of glaucoma or macular degeneration.
Because eye exams can pick up systemic conditions like diabetes and high blood pressure before other symptoms appear, regular visits to an O.D. serve as more than just a vision check. They function as a broader health screening, particularly for people who may not see a primary care physician regularly.