Ophthalmologist: Definition and Overview

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What Is An Ophthalmologist

What is an opthalmologist?

An ophthalmologist is a medical doctor specializing in diseases of the eye. People often get confused between opticians, optometrists, and ophthalmologists.

What is the difference between an optometrist and an ophthalmologist?

An optician can fill prescriptions for corrective lenses but does not examine the eyes.

An optometrist has a postgraduate doctorate degree (an OD) from a school of optometry but is not a medical doctor (an MD). Optometrists are primarily responsible for treating refractive disorders such as nearsightedness and prescribing corrective lenses. Although optometrists can sometimes detect and manage other eye disorders, and they can prescribe drugs if they are certified by their state board of optometry, they cannot perform surgery.

Keep an eye on your vision! Learn about preventive steps and treatments for diabetic retinopathy from retinal specialist Dr. Charles Wykoff. >>

An ophthalmologist has a degree from a medical school (an MD) and must have completed three to six years of specialized training in a residency program. Unlike an optometrist, an ophthalmologist is qualified to perform surgery on the eye.

What does an ophthalmologist do?

In addition to treating refractive disorders, an ophthalmologist diagnoses and treats diseases of the eye, including different kinds of infections, cataracts (clouding of the lenses), glaucoma (increased pressure inside the eye, leading to damage to the optic nerve), macular degeneration (age-related degeneration of the central part of the vision), and diabetic retinopathy (damage to the blood vessels supplying the retina of the eye). Often, ophthalmologists can detect systemic diseases such as high blood pressure, stroke, and cancer through examination of the eyes. In fact, it is sometimes the ophthalmologist who first discovers that a person has diabetes through changes in the retina.

Eye doctors use a number of tools for examining and evaluating the eye, including the following:

    • A medical history, in which the eye doctor asks about any changes in vision and general health problems.


    • A vision chart to evaluate visual acuity and an assortment of corrective lenses to see which improve vision. These tools help diagnose refractive problems.


    • A slit-lamp microscope, which shines light into the eyes, to examine the inside of the eyelids, the front surface of the eye, and the inner eye under magnification.


    • Eye drops, one set to anesthetize the eyes and another set to dilate the pupils, to make it easier to more fully view the eye. Once the pupils are dilated, the doctor uses an ophthalmoscope to visualize and evaluate the vitreous (the gel that fills the inside of the eye) and the retina.


  • A device called a tonometer to measure the pressure on the inside of the eye and diagnose conditions such as glaucoma.

Major health organizations agree that people with diabetes should get an eye examination that includes dilation of the pupil every year to detect diabetic retinopathy. Unfortunately, many people do not get a yearly eye exam; one recent study reported that less than half of all people with diagnosed diabetes had undergone an eye examination in the past year. Currently, despite medical advances in the treatment of diabetic retinopathy, between 12,000 and 24,000 new cases of blindness related to diabetes are reported every year. Many of these could be prevented if problems were diagnosed and treated early. Routine eye examinations can also uncover other serious eye diseases, including cataracts (which are also more common in people with diabetes), glaucoma, and macular degeneration.

Originally Published May 18, 2006

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