Examining The Internal Eye - The Eye Examination: The Aging Eye Preventing And Treating Eye Disease
Content provided by the Faculty of the Harvard Medical School
Examining the internal eye
Using a slit lamp, a diagnostic tool with a powerful microscope and a narrow slit of light, the doctor can explore different levels of the eye's transparent tissue and assess the inner workings of the eye. As you keep your head steady on a chin rest, beams of light are projected onto and into your eye. The instrument's use of narrow light beams and high magnification provides an important cross-sectional picture of eye tissue. This gives the doctor a close-up view of the cornea, anterior chamber, lens, and vitreous humor. The doctor will check for many things, including degeneration or the presence of foreign particles in the cornea, inflammation within the anterior chamber, cataract, floaters, and tumors or abnormal blood vessels in the iris.
Testing pupil dilation
The doctor may apply drops of a mydriatic drug to your eyes. This dilates your pupils, allowing a better examination of the eye's interior. The drops take time to wear off, so people often experience light sensitivity and difficulty focusing on close tasks for several hours afterward. Reversal drops can shorten this period. It is difficult to drive while your eyes are dilated.
Measuring eye pressure (tonometry)
This painless test to measure eye pressure can detect possible signs of glaucoma. After the eye is numbed with anesthetic drops, the doctor touches the cornea with an instrument called an applanation tonometer to measure the eye's resistance. In alternate — but less accurate — procedures, a puff of air is blown against the eye to determine what force it takes to flatten the cornea, or an instrument called a tonometer is used to measure pressure. Anyone at risk for glaucoma, including anyone who is over age 40 or who has a borderline result with the puff-of-air test, should be tested with the more accurate applanation tonometer.
Viewing the retina and optic nerve
Finally, the doctor will use a hand-held ophthalmoscope, with focusing lenses and a light source or the slit lamp, to look more deeply into your eye to evaluate the clarity of the lens and vitreous humor and the health of the retina, macula, optic nerve, and their blood vessels.
In special circumstances, the doctor will use different lenses to view the far periphery of the retina. The light source may be mounted on the doctor's head or on the slit lamp.
Your eye professionalsIf you've ever been confused about whether you need to see an ophthalmologist, optometrist, or optician, you're not alone. Although the names of these specialists sound similar, each plays a distinct role in eye care. Because the training and experience of each specialist varies, it is important to seek the services of the appropriate professional for your eye care needs. Ophthalmologist. An ophthalmologist is a physician — either a doctor of medicine (M.D.) or doctor of osteopathy (D.O.) — who specializes in medical and surgical care of the eyes and visual system, as well as in prevention of eye disease. In order to become a licensed ophthalmologist, a doctor must complete four or more years of medical school, one year of internship, and three or more years of specialized medical, surgical, and refractive training. Ophthalmologists are qualified to diagnose and treat (medically and surgically) all diseases, disorders, and injuries of the eyes and visual system. In addition, they may provide more basic eye care, including prescribing eyeglasses and contact lenses. Ocuplastic specialist. This is an ophthalmologist who has received advanced training in plastic and reconstructive surgery of the eye and surrounding structures. Ocuplastic specialists are often consulted for problems with the eyelids, tear drainage, and skin cancer around the eyes. Optometrist. An optometrist, or doctor of optometry, is a health service provider who deals with vision problems. Optometrists must complete a four-year course at an accredited college of optometry, but they do not attend medical school and are not trained to perform surgery. They are licensed by the state to examine the eyes, determine the presence of vision problems (including eye diseases), recommend eye exercises, and prescribe eyeglasses and contact lenses. In many states, optometrists are permitted to treat certain eye conditions with medications. Normally, if an optometrist diagnoses a serious eye disorder in a patient, he or she will refer that person to an ophthalmologist. Optician. An optician is a technician who makes and fits eyeglasses, contact lenses, or other optical devices after they have been prescribed by an ophthalmologist or optometrist. |
| Last updated: | June 19, 2007 |
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Medical content reviewed by the Faculty of the Harvard Medical School. Harvard Health Publications, Copyright © 2007 by President and Fellows of Harvard College. All rights reserved. Used with permission of StayWell.
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