Eye Exams

Preparing for an Eye Exam

Eyecare experts recommend you have a complete eye exam every one to three years, depending on your age, risk factors, and physical condition.

Children. Some experts estimate that approximately 5 percent to 10 percent of preschoolers and 25 percent of school-aged children have vision problems. According to the American Optometric Association (AOA), all children should have their eyes examined at 6 months of age, at age 3 and again at the start of school. Children without vision problems or risk factors for eye or vision problems should then continue to have their eyes examined at least every two years throughout school.

Children with existing vision problems or risk factors should have their eyes examined more frequently. Common risk factors for vision problems include:

• Premature birth
• Developmental delays
• Turned or crossed eyes
• Family history of eye disease
• History of eye injury
• Other physical illness or disease

The AOA recommends that children who wear eyeglasses or contact lenses should have their eyes examined at least every 12 months or according to their eye doctor's instructions.

Adults. The AOA also recommends an annual eye exam for any adult who wears eyeglasses or contacts. If you don't normally need vision correction, you still need an eye exam every two years up to the age of 40, depending on your rate of visual change and overall health. Doctors often recommend more frequent examinations for adults with diabetes, high blood pressure and other disorders, because many diseases can have an impact on vision and eye health.

If you are over 40, you may need to be examined more frequently than every other year to check for common age-related eye problems such as presbyopia, cataracts and macular degeneration.

Because the risk of eye disease continues to increase with advancing age, everyone over the age of 60 should be examined annually.

Who Should I See for My Eye Exam?

There are two kinds of eye doctors - ophthalmologists and optometrists. Who you should see depends on your needs and preferences.

Ophthalmologists are medical doctors (MDs or DOs) who specialize in eyecare. In addition to prescribing eyeglasses and contacts, ophthalmologists are licensed to perform eye surgery and treat medical conditions of the eye. Ophthalmologists generally undergo eight or more years of training after college.

Optometrists (ODs) are eye doctors who can prescribe glasses and contacts and treat medical conditions of the eye with eye drops and other medicines. They are not licensed to perform eye surgery. Optometrists generally receive four or more years of training after college.

How Much Does an Eye Exam Cost?

Eye exams are available in many settings, from discount optical stores to surgical offices, so the fees can vary widely. Additionally, fees can vary depending on whether the exam is performed by an optometrist or an ophthalmologist, and the type of services that are included in the exam.

Generally speaking, contact lens exams cost more than regular eye exams. Likewise, an additional or higher fee may be charged for specialized services such as laser vision correction evaluations.

Many insurance plans cover at least a portion of eye exam services. Check to see what your benefits are and which eye doctors in your area participate in your plan before you make an appointment. Then be sure to give your doctor's office your insurance information to verify coverage.

What Information Should I Take with Me to My Eye Exam?

It's important to have some basic information ready at the time of your eye examination. Bring the following items to your exam:

• All eyeglasses and contact lenses you use routinely, including reading glasses.
• A list of any medications you take (including dosages).
• A list of any nutritional supplements you take (including dosages).
• A list of questions to ask the doctor, especially if you are interested in contact lenses or laser vision correction surgery.

Finally, also bring your medical or vision insurance card if you will be using it for a portion of your fees.

Your Comprehensive Eye Exam

A comprehensive eye exam includes a number of tests and procedures to examine and evaluate the health of your eyes and the quality of your vision. These tests range from simple ones, like having you read an eye chart, to complex tests, such as using a high-powered lens to examine the health of the tissues inside of your eyes.

 Here are some tests you are likely to encounter during a routine comprehensive eye exam:

Retinoscopy

This test helps your doctor get a good approximation of your eyeglasses prescription. For retinoscopy, the room lights are dimmed and an instrument containing wheels of lenses (called a phoropter) is positioned in front of your eyes. You will be asked to look at an object across the room (usually the big "E" on the wall chart or screen) while your doctor shines a light from a hand-held instrument into your eyes from arm's length and flips different lenses in front of your eyes.

Based on the way the light reflects from your eye during this procedure, your doctor can get a very good idea of what your eyeglasses prescription should be. This test is especially useful for children and non-verbal patients who are unable to accurately answer the doctor's questions.

With the widespread use of automated instruments to help determine eyeglass prescriptions today, many doctors forgo performing retinoscopy during comprehensive eye exams. However, this test can provide valuable information about the clarity of the internal lens and other media inside the eye. So doctors who no longer perform this test routinely may still use it when examining someone who may be at risk of cataracts or other internal eye problems. 

Refraction

This is the test your doctor uses to determine your exact eyeglasses prescription. During refraction, the doctor puts the phoropter in front of your eyes and shows you a series of lens choices. He or she will then ask you which one of the two lenses in each choice ("1 or 2," "A or B," for example) makes the letters on the wall chart look clearer.

Based on your answers, your doctor will determine the amount of nearsightedness, farsightedness and/or astigmatism you have, and the eyeglass lenses required to correct these vision problems (which are called refractive errors). 

Autorefractors and Aberrometers

Your eye doctor also may use an autorefractor or aberrometer to help determine your glasses prescription. With these devices, you rest your chin and head on the instrument and look ahead at a pinpoint of light or other image. 

An autorefractor evaluates the way images focus on your retina, where vision processing takes place, without the need for you to say anything. This makes autorefractors especially useful when examining young children or people who may have difficulty with a regular ("subjective") refraction. Automated refractions and subjective refractions are often used together during a comprehensive exam to determine your eyeglasses prescription.

An aberrometer uses advanced wavefront technology to detect even obscure vision errors based on the way light travels through your eye.

Cover Test

While there are many ways for your eye doctor to check how your eyes work together, the cover test is the simplest and most common.

During a cover test, the eye doctor will have you focus on a small object at distance and will then cover each of your eyes alternately while you stare at the target. As they do this, eye doctors observe how much each eye has to move when uncovered to pick up the fixation target. The test is then repeated as you focus on a near object.

Cover tests can detect even very subtle misalignments that can interfere with your eyes working together properly (binocular vision) and cause amblyopia or "lazy eye."

Slit-Lamp Examination

The slit lamp is an instrument that the eye doctor uses to examine the health of your eyes. Also called a biomicroscope, the slit lamp gives your doctor a highly magnified view of the structures of the eye, including the lens behind the pupil, in order to thoroughly evaluate them for signs of infection or disease.

The slit lamp is basically an illuminated microscope that's mounted on a table and includes a chin and head rest so you can rest comfortably while the doctor looks at your eyes. After the doctor looks at the front of your eye, additional hand-held lenses may be used to also examine your retina (the light-sensitive inner lining of the back of the eye.)

Tonometry (Glaucoma Testing)

Tonometry is the name for a variety of tests that can be performed to determine the pressure inside your eye. Elevated internal eye pressure can cause glaucoma, which is vision loss due to damage to the sensitive optic nerve in the back of the eye.

One common method used for tonometry is the "air puff" test - where an automated instrument discharges a small burst of air to the surface of your eye. Based on your eye's resistance to the puff of air, the machine calculates the pressure inside your eye - called your intraocular pressure (IOP). 

Though the test itself can be startling, nothing but air touches your eye during this measurement, and there's no risk of eye injury from the air puff test.

Another popular way to measure eye pressure is with an instrument called an applanation tonometer, which is usually attached to a slit lamp. For this test, a yellow eye drop is placed on your eyes. Your eyes will feel slightly heavy when the drops start working. This is not a dilating drop — it is simply a numbing agent combined with a yellow dye. Then the doctor will have you stare straight ahead in the slit lamp while he or she gently rests the bright-blue glowing probe of the tonometer on the front of each eye and manually measures the intraocular pressure. 

Like the air puff test, applanation tonometry is painless and takes just a few seconds. 

Since glaucoma is often the result of an increase of pressure inside the eye, these are important tests for ensuring the long-term health of your eyes.

Pupil Dilation

Your comprehensive exam may include the use of dilating drops. These medicated eye drops enlarge your pupil so your doctor can get a better view of the internal structures in the back of the eye. Dilating drops usually take about 20 minutes to start working. When your pupils are dilated, you will be sensitive to light, because more light is getting into your eye. You may also notice difficulty reading or focusing on close objects. These effects can last for up to several hours, depending on the strength of the drops used.

If you don't have sunglasses to wear after the exam, disposable sunglasses will be provided to help you drive home. Dilation is very important for people with risk factors for eye disease, because it allows for a more thorough evaluation of the health of the inside of your eyes.

Summary

These are the most common tests performed during a standard comprehensive eye exam. Depending on your particular needs, your doctor may perform additional tests or schedule them to be performed at a later date.

Eye Exams for Children

As a parent, you may wonder whether your pre-schooler has a vision problem or when a first eye exam should be scheduled.

Eye exams for children are extremely important. Experts say 5% to 10% of pre-schoolers and 25% of school-aged children have vision problems. Early identification of a child's vision problem is crucial because, if left untreated, some childhood vision problems can cause permanent vision loss.

When Should Kids Have Their Eyes Examined?

According to the American Optometric Association (AOA), infants should have their first comprehensive eye exam at 6 months of age. Children then should receive additional eye exams at 3 years of age, and just before they enter kindergarten or the first grade at about age 5 or 6.

For school-aged children, the AOA recommends an eye exam every two years if no vision correction is required. Children who need eyeglasses or contact lenses should be examined annually or according to their eye doctor's recommendations.

Early eye exams also are important because children need the following basic visual skills for learning:

• Near vision
• Distance vision
• Eye teaming (binocularity) skills
• Eye movement skills
• Focusing skills
• Peripheral awareness
• Eye/hand coordination

Because of the importance of good vision for learning, some states require an eye exam for all children entering school for the first time. 

Scheduling Your Child's Eye Exam

Your family doctor or pediatrician likely will be the first medical professional to examine your child's eyes. If eye problems are suspected during routine physical examinations, a referral might be made to an ophthalmologist or optometrist for further evaluation. Eye doctors have specific equipment and training to help them detect and diagnose potential vision problems.

When scheduling an eye exam, choose a time when your child is usually alert and happy. Specifics of how eye exams are conducted depend on your child's age, but an exam generally will involve a case history, vision testing, determination of whether eyeglasses are needed, testing of eye alignment, an eye health examination and a consultation with you regarding the findings.

After you've made the appointment, you may be sent a case history form by mail, or you may be given one when you check in at the doctor's office. The case history form will ask about your child's birth history (also called perinatal history), such as birth weight and whether the child was full-term. Your eye doctor also may ask whether complications occurred during the pregnancy or delivery. The form will also inquire about your child's medical history, including current medications and past or present allergies.

Be sure to tell your eye doctor if your child has a history of prematurity, has delayed motor development, engages in frequent eye rubbing, blinks excessively, fails to maintain eye contact, cannot seem to maintain a gaze (fixation) while looking at objects, has poor eye tracking skills or has failed a pediatrician or pre-school vision screening.

Your eye doctor will also want to know about previous ocular diagnoses and treatments involving your child, such as possible surgeries and glasses or contact lens wear. Be sure you inform your eye doctor if there is a family history of eye problems requiring vision correction, such as nearsightedness or farsightedness, misaligned eyes (strabismus) or amblyopia ("lazy eye").

Eye Testing for Infants

It takes some time for a baby's vision skills to develop. To assess whether your infant's eyes are developing normally, your eye doctor may use one or more of the following tests:

• Tests of pupil responses evaluate whether the eye's pupil opens and closes properly in the presence or absence of light.
• "Fixate and follow" testing determines whether your baby can fixate on an object (such as a light) and follow it as it moves. Infants should be able to perform this task quite well by the time they are 3 months old.
• Preferential looking involves using cards that are blank on one side with stripes on the other side to attract the gaze of an infant to the stripes. In this way, vision capabilities can be assessed.

Eye Testing for Pre-School Children

Pre-school children can have their eyes thoroughly tested even if they don't yet know the alphabet or are too young or too shy to answer the doctor's questions. Some common eye tests used specifically for young children include:

• LEA symbols for young children are similar to regular eye tests using charts with letters, except that special symbols in these tests include an apple, house, square and circle.
• Retinoscopy is a test that involves shining a light into the eye to observe how it reflects from the retina (the light-sensitive inner lining of the back of the eye). This test helps eye doctors determine the child's eyeglass prescription.
• Random dot stereopsis uses dot patterns to determine how well the two eyes work as a team.

Eye and Vision Problems that Affect Children

Besides looking for nearsightedness, farsightedness and astigmatism (refractive errors), your eye doctor will examine your child's eyes for signs of the following eye and vision problems commonly found in young children:

• Amblyopia. Also called "lazy eye," this is decreased vision in one or both eyes despite the absence of any eye health problem or damage. Common causes of amblyopia include strabismus (see below) and a significant difference in the refractive errors of the two eyes. Treatment of amblyopia may include patching the dominant eye to strengthen the weaker eye.

• Strabismus. This is misalignment of the eyes, often caused by a congenital defect in the positioning or strength of muscles that are attached to the eye and control eye positioning and movement. Left untreated, strabismus can cause amblyopia in the misaligned eye. Depending on its cause and severity, surgery may be required to treat strabismus.

• Convergence insufficiency. This is the inability to keep the eye comfortably aligned for reading and other near tasks. Convergence insufficiency can often be treated successfully with vision therapy, a specific program of eye exercises.

• Focusing problems. Children with focusing problems (also called accommodation problems) may have trouble changing focus from distance to near and back again (accommodative infacility) or have problems maintaining adequate focus for reading (accommodative insufficiency). These problems often can be successfully treated with vision therapy.

• Eye teaming problems. Many eye teaming (binocularity) problems are more subtle than strabismus. Deficiencies in eye teaming skills can cause problems with depth perception and coordination.

Vision and Learning 

Experts say that 80% of what your child learns in school is presented visually. Undetected vision problems can put them at a significant disadvantage. Be sure to schedule a complete eye exam for your child prior to the start of school.