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Learning the Three O's of Eye Care

In the United States, three primary type of eye care professionals provide services. As a consumer, it is important to understand the differences in the three o’s: Ophthalmologists, Optometrists, and Opticians. Qualifications for these professions differ in education, training and credentials. Outlined below are the differences to watch for when selecting a provider.


An ophthalmologist is a physician who specializes in the medical and surgical care of the eyes and visual system and in the prevention of eye disease and injury. They provide a full spectrum of care including routine eye exams, diagnosis and medical treatment of eye disorders and diseases, prescriptions for eyeglasses, surgery, and management of eye problems that are caused by systemic illnesses. Ophthalmologists can be medical doctors (M.D.) or doctors of osteopathy (D.O.).


After completing 4 years of undergraduate study at a college or university, ophthalmologists attend 4 years of medical school to obtain an M.D. or D.O. degree. After graduating from medical school, they complete a 1-year internship and 3 years of training in ophthalmology in a residency program approved by the Accreditation Council for Graduate Medical Education (ACGME). Following residency, ophthalmologists may enroll in a 1- to 2-year fellowship program.

A fellowship offers the opportunity to develop expertise in a subspecialty such as:

  • Corneal diseases

  • Retina and vitreous diseases

  • Glaucoma

  • Pediatric eye problems

  • Plastic surgery

Ophthalmologists are licensed by a state regulatory board to practice medicine and surgery. In addition, they are board certified, which means that they have passed a rigorous two-part examination that tests their knowledge and ability to provide expert care. The examination is administered by the American Board of Ophthalmology, and if the doctor passes, he or she becomes a board-certified ophthalmologist.

Subspecialties in Ophthalmology

The following are subspecialties in ophthalmology:

  • Cornea and External Disease: This subspecialty involves the diagnosis and management of diseases of the cornea, sclera, conjunctiva and eyelids, including corneal dystrophies, microbial infections, conjunctival and corneal tumors, inflammatory processes and anterior ocular manifestations of systemic diseases. Training in this area frequently includes corneal transplant surgery and corneal surgery to correct refractive errors.

  • Glaucoma: This subspecialty includes the treatment of glaucoma and other disorders that may cause optic nerve damage by increasing intraocular pressure. This area involves the medical and surgical treatment of both pediatric and adult patients.

  • Neuro-Ophthalmology: Involving the relationship between neurologic and ophthalmic diseases, neuro-ophthalmology also deals with local pathology affecting the optic nerve and visual pathways. Over 50 percent of all intracranial lesions involve the visual or oculomotor pathways. Neuro-ophthalmology is generally practiced as a nonsurgical subspecialty but can be combined with surgery of the eye and orbit.

  • Ophthalmic Pathology: The ophthalmic pathologist has training in both ophthalmology and pathology, typically in that order. Because of the unique combination of skills involved in this subspecialty, it is usually the ophthalmic pathologist, rather than the general pathologist, who examines tissue specimens from the eye and adnexa.

  • Ophthalmic Plastic Surgery: The specialty of ophthalmology includes oculofacial plastic surgery. This combines orbital and periocular surgery with facial plastic surgery and includes the clinical practice of aesthetic plastic and reconstructive surgery of the face, orbit, eyelid, and lacrimal system. With this unique combination of skills ophthalmologists perform facial plastic surgery, eyelid surgery, orbital surgery and lacrimal surgery.

  • Pediatric Ophthalmology: The bulk of pediatric ophthalmic practice involves the medical and surgical management of strabismus, amblyopia, genetic and developmental abnormalities and a wide range of inflammatory, traumatic and neoplastic conditions occurring in the first two decades of life. This subspecialty also deals with the ocular manifestations of certain systemic disorders.

  • Vitreoretinal Diseases: This subspecialty involves both the medical and surgical treatment of retinal and vitreoretinal disease. The types of diseases treated include manifestations of local, systemic and genetic diseases as they affect the retina and vitreous. Diagnosis involves the use and interpretation of ultrasound, fluorescein angiography and electrophysiology. Treatment methods include laser therapy, cryotherapy, retinal detachment surgery and vitrectomy (removal of the vitreous).


Optometrists, also called doctors of optometry (O.D.) diagnose and treat vision problems, eye diseases and related conditions, and prescribe eyeglasses, contact lenses, and medications to treat eye disorders. They cannot perform surgery, but they often provide patients with pre- and postsurgical care. Sometimes ophthalmologists and optometrists work in the same practice and co-manage patients.


Optometrists must complete at least 3 years of study at an accredited college or university before beginning optometry training; however, most optometry students have a bachelor's degree or higher. Next, they must attend an accredited 4-year optometry school and, after graduation, they must pass written and clinical state board examinations. Some optometrists go on to obtain a master's degree or Ph.D. in visual science, physiological optics, neurophysiology, or public health.

A 1-year postgraduate clinical residency is available for optometrists who want to specialize in one of the following areas:

  • Contact lenses

  • Family practice optometry

  • Geriatric optometry

  • Hospital-based optometry

  • Ocular disease

  • Pediatric optometry

  • Primary care optometry

  • Vision therapy


A dispensing optician fits eyeglasses and, in some states, contact lenses. They analyze and interpret prescriptions written by ophthalmologists or optometrists to determine which eyeglasses or contact lenses are best suited to the patient's lifestyle and visual needs.

The optician takes eye measurements to insure proper lens placement in the eyeglasses' frame and verifies the accuracy of the finished product. She or he also may manufacture (grind) lenses from raw materials and cut them to fit into the frame. Before designing contact lenses, the optician evaluates the patient's eyes under a special microscope and measures the curvature of the eye. The optician instructs the patient in the care and handling of contact lenses.

Opticians may hold an associate opticianry degree or may have apprenticed for a required number of hours. In most states that require an optician to be licensed, candidates must pass an examination given by the American Board of Opticianry (ABO). Some states also require that candidates pass a state board exam. Opticians can take the National Contact Lens Examination (NCLE), which in certain states allows them to fit and dispense contact lenses.

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