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What You Need To Know About Eye Examinations

By: James Auran, MD

When Should I Have My Eyes Examined?

Adults
If you are an adult without risk factors for eye disease, The American Academy of Ophthalmology recommends that you have an eye examination at least once between the ages 20 and 39, every two to four years between ages 40 and 64, and every one to two years if you are 65 or older. If you are African-American or have a family history of glaucoma, you should be examined every three to five years between 20 and 39 years of age, every two to four years between ages 40 and 64, every one to two years if you are older than 65. People with diabetes should receive an examination by an eye doctor at least once a year.

Children
The American Academy of Ophthalmology and the American Association for Pediatric Ophthalmology and Strabismus (http://med-aapos.bu.edu/AAPOS/Screening.html) recommend that a pediatrician or family physician examine infants in the nursery and that high-risk infants be examined by an ophthalmologist. Children’s eyes should be screened by their pediatrician, family physician, or ophthalmologist at ages six months, three and one-half years, and five years. After that, screening should be performed at routine school examinations or if eye symptoms are present. Routine examinations by an ophthalmologist are not of significant benefit.

Who Should Examine My Eyes?

Eye examinations are performed by eye doctors--ophthalmologists (eye MDs) or optometrists (doctorates of optometry). In some cases, assistants or technicians may perform portions of the examination. In general, the quality of the examination depends on the training, experience, and intelligence of the examiner, as well as the thoroughness and duration of examination.

Examination Preparation
Remember to bring a list of all your medications. If your history is complicated, old medical records or a report from your previous doctor can be invaluable. If you anticipate that the doctor will dilate your pupils (ask about this at the time you schedule the appointment), plan on not driving for four hours after the examination. Clarify with the doctor’s office your insurance coverage and the procedure that you and the doctor must follow to obtain optimum insurance coverage for the visit. In particular, if your insurer requires pre-certification, make sure the doctor’s office has this before you are seen.

The Eye Examination
The following is a description of the various stages of an eye exam:

History
The history you provide your eye doctor is often the most important part of the encounter. Be prepared to provide a comprehensive medical history. A thorough history includes family history (especially of glaucoma, cataracts, retinal detachments, macular degeneration, diabetes, migraines), and your medications, allergies, and previous eye problems. When giving a history of medications to your doctor, remember to include aspirin, asthma inhalers, steroid nasal sprays, steroid skin ointments, vitamins, and nutritional supplements, all of which can affect the eye or impact upon eye surgery. If you have ever been told that you have lazy eye (amblyopia), let your doctor know. It is also important to let the doctor know if you are or could be pregnant, or if you are nursing a child. Medical history information is often obtained by the doctor via a written questionnaire.

Physical examination
Many people are squeamish about their eyes, which is perfectly natural. An experienced eye doctor can make the examination experience minimally uncomfortable. The purpose of the exam is to determine how well the eye is working and if all its parts are intact.

Visual function
The examination usually begins with testing your eyesight by reading the eye chart, at far, intermediate (computer screen distance), and near (reading) distances. If your vision is not as good as it should be, refraction may be performed, in which lenses are placed in front of the eye to optimize your visual acuity. The eye doctor may then work with you to determine if glasses or contact lenses are appropriate and, if so, what type(s) will work best for you.

The pupil is the opening in the center of your iris (colored portion of the eye) through which light passes into the back of the eye. When you look at another person's eye, the pupil is the black spot in the center of the iris. The doctor will test your pupil function, by shining a flashlight into each eye separately and then alternating between the eyes. The doctor may crudely test your peripheral vision by having you count his/her fingers (or by having you correctly indicate when they are moving) when they are positioned well away from the direction at which you are looking.

The muscles controlling the eyes will be tested to determine if the eyes move appropriately in every direction: alone and together as a pair. Any double vision or tendency towards double vision will be evaluated and treated if appropriate.

Slit lamp examination
The next portion of the examination will occur with you sitting at the slit lamp, a binocular microscope that the doctor uses to examine your eyes under high magnification. It is very important that the doctor positions you comfortably or it will be difficult to hold still during the examination. The slit lamp allows the doctor to perform a detailed examination of the lids, the white of the eye (conjunctiva and sclera), the cornea (the clear front window in front of the iris and pupil through which light enters the eye), the iris, and your crystalline lens.

The front part of your eye is filled with fluid, which continually percolates through the eye, bringing oxygen and nutrients to the cornea and lens, neither of which has a supply of blood. During the slit lamp examination, a measurement of the fluid pressure within the eye will be performed to determine if you might have glaucoma. Glaucoma is a disorder in which the fluid pressure in the eye goes up, pressing on the optic nerve and eventually damaging or destroying it. Anesthetic eye drops will be applied to your eyes prior to this test. These drops sting for up to a minute and then leave the eye numb and feeling full or heavy for 10 to 15 minutes. Your throat may also feel numb from the drops draining into your nose and throat via your tear drainage system.

The measurement of eye pressure involves touching each eye with a probe, called an applanation tonometer, for just a few seconds. The surface of this probe is smooth plastic and it is possible, but highly unlikely, to scratch the surface of your eye during this test. The back of the eye may be examined with a very intense light during the slit lamp examination.

Fundoscopy
The pupil is typically small enough to limit the doctor’s view into your eye. For this reason, dilating eye drops, which enlarge the pupil for two to four hours, are routinely given prior to examination of the back of the eye. These drops should not hurt because the eye should still be numb from the anesthetic drops. With dilation, you may find your vision blurred and the world will appear very bright, especially outdoors. The instruments used to examine the back of the eye project intense light into your eyes. Reducing the intensity of the light may limit the doctor’s view, but if the bright light is too uncomfortable, it is appropriate for you to ask that the intensity be reduced if possible. Fortunately, the eye adapts somewhat to the intense light and the discomfort often abates as the examination progresses.

The back of your eyes will be examined with the hand-held direct ophthalmoscope. This provides a high magnification view of the very back of your eye and allows the examiner to evaluate the retina (the nerve layer in the back of the eye that contains the sensory cells, or photoreceptors), blood vessels, and optic nerve. This portion of the exam is particularly helpful in identifying age-related macular degeneration and abnormalities of the optic nerve such as glaucoma damage.

After donning a headset, the doctor next examines your eye with a binocular indirect ophthalmoscope. This gives the doctor a panoramic view of the entirety of the back of your eye, looking for retinal holes, tears or detachments, moles, tumors, or abnormal blood vessels. Because the doctor can only view a portion of the back of the eye at any one time, he or she will instruct you to look in different directions in order to view all of the posterior pole.

Pupillary dilation can distort the vision enough to impair the ability to drive for two to four hours. You can ask your doctor to use weak dilating drops (e.g., 0.5 percent tropicamide) and give you reversing drops (dapiprazole or Rev-Eyes) to hasten recovery after dilation.

Specialized examinations: visual fields
Should there be a suspicion that your peripheral vision is impaired, or could be in the future, your doctor may order a formal visual field test. Computerized visual field testing (e.g., Humphrey visual fields) is most commonly used. In this test, you will be asked to look at a central, fixed point while tiny lights are illuminated in the periphery and you will be asked to press a button when you see the peripheral light go on. The test takes about 20 minutes.

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After the Examination

Occasionally, patients have unusually long recovery from the dilating drops, resulting in blurry vision that lasts a day or two. Some patients experience irritation after an eye examination due to the eye drops or the glaucoma test. This occurs most often in people whose eyes are irritated before the examination even starts. Such irritation can be relieved by using lubricating eye drops and/or applying a warm compress to the eyes. If the instructions given to you by your physician are not clear or you are concerned that you will not remember them, request written instructions. Review your written prescriptions to make sure that they are legible and that they match the instructions given by the doctor. You may request that a report be sent by your eye doctor to your medical doctor if this will be a significant help in your overall medical care.

Diagnostic eye drops and pregnancy or breast-feeding
Diagnostic eye drops have been used for decades in pregnant women and no adverse effects have been reported. However, no controlled studies in humans have been performed for any ophthalmic diagnostic drops. In pregnant animal studies, the only diagnostic eye drops that did not adversely affect the fetus are lidocaine and fluorescein.

If you are pregnant, in most instances, you can have your eyes examined without the use of diagnostic drops. The use of any drops for eye examinations in pregnant women should be used only with the patient’s knowledge and the understanding that the need for the drop outweighs any theoretical risk to the fetus.

Medically necessary medications should not be avoided during pregnancy. However, if you are to get eye drops during your examination, you should ask the doctor to take steps to reduce absorption of the drops into your bloodstream (e.g., pressing on the tear ducts after drop instillation, using diluted drops) and consider using only lidocaine and fluorescein during the examination (eliminating dilating drops if possible). Minimizing eye drops during the period in which the fetal organs form (weeks three to eight) is a good general principle.

The American Academy of Pediatrics states that the ophthalmic diagnostic agents lidocaine, fluorescein dye, atropine, and scopolamine are usually compatible with breast-feeding. Of the commonly used diagnostic drops, only homatropine has a warning against its use during breast-feeding. All others have been widely used for decades without reports of adverse reactions to the nursing infant.

Are Diagnostic Eye Drops Safe for Adults?

Yes. However, dilating drops should be avoided if you are at risk for narrow-angle glaucoma. Phenylephrine should not be used if you are taking a certain type of antidepressant (a monoamine oxidase or MAO inhibitor) and should be used with caution if you have significant hypertension or cardiovascular disease.

Are Diagnostic Eye Drops Safe for Children?

The eye drops used during an eye examination (anesthetics, fluorescein, and dilating drops) are not approved by the FDA for use in children because there have been no formal studies that prove their safety. Nevertheless, the drops have been used widely for decades and are considered by eye doctors to be safe and effective. However, a high (10 percent) concentration of phenylephrine should not be used in children, and drops should not be administered to children at intervals shorter than recommended by the manufacturer.

Are the Bright Lights Used During the Examination Safe?

Yes, more or less. However, prolonged exposure to light from the indirect ophthalmoscope presents a potential hazard of damaging the retina and diminishing vision. However, the known benefits of examination by a competent doctor outweigh the theoretical risk of harm by a huge margin.

Will Insurance Cover the Eye Examination?

Many people are under the mistaken impression that their medical insurance does not usually cover eye examinations. However, medical insurance will cover your ophthalmic examination if you have a specific complaint (e.g., blurred vision, headaches, eye fatigue, floating spots, ocular irritation, etc.) even if your primary reason for going to the doctor is for a checkup. Most insurance plans will not cover eye checkups unless you have eye complaints. Even if you go to your doctor with an eye-related complaint, some insurance companies may not cover your examination if the cause of the complaint is due to a need for glasses or a change of an eyeglass prescription.

Most medical insurance policies do not cover refractions (the portion of the examination in which the optimal power of your glasses and/or contact lenses is determined) or the fitting or purchase of contact lenses or glasses. These insurance policies allow the physician to bill you directly for the refraction.

Some insurance companies offer optional vision-care riders or vision-care plans. These cover eye checkups at specified intervals and pay for some (often bare-bones level) refractive services (refraction, contact lenses, and glasses). The doctor is reimbursed by the insurer at a marked discount for eye examinations performed under these vision-care riders/plans. Therefore, many doctors do not participate in these plans and the vision-care rider/plan eye examinations can be rather cursory.

Children
Insurers often pick up the tab for eye examinations in children who have no eye complaints. If not, the rules are the same as with adults.

Other Considerations

Financial and time pressures may compel doctors to skip or give short shrift to portions of the examination. To a degree, it is a matter of getting what you pay for. On the other hand, if you visit a doctor with the expectation of getting a full examination, you should get one. If you do not feel that the doctor performed an adequate examination, it is in your best interest to make this known.

Some eye doctors make up to half their income from eyeglass and contact lens dispensing. Not surprisingly, doctors who own an optical shop prescribe many more eyeglasses than those who do not own an optical shop. The financial incentive to prescribe glasses is especially strong with examinations performed under vision-care plans where the doctor is paid poorly for the examination.