Routine Eye Exams

Topics on this page include:

Understanding visual acuity

Most people think that when the eye professional checks their vision, he or she is measuring what the person can see without glasses or other corrective lenses. However, most doctors think of vision as corrected visual acuity. Visual acuity is the measurement of the ability to see. It is a measurement of the smallest object a person can see without corrective lenses, or with glasses or contact lenses, if they are needed. The goal of eye professionals is to improve the patient's corrected visual acuity.

In most cases, people's eyes won't get any worse if they don't wear their glasses or if they wear glasses with an incorrect prescription. The one exception is infants and toddlers who have amblyopia -- they must have their vision corrected to prevent vision loss. If children who are farsighted don't wear their glasses, they may have trouble accepting a full prescription later.

Importance of regular eye exams

Most people make regular visits to their medical doctor and to their dentist, but not to their eye doctor. Eighty percent of all the sensory information our brains receive comes from our eyes. Our eyes are extremely important to us and to our quality of life. Regular eye exams should be part of everyone's health care regime, especially those who suffer from chronic health conditions such as diabetes or high blood pressure.

If you experience any changes in your vision between regularly scheduled visits with your eye specialist, you should call and arrange to be checked as soon as possible. Early detection of problems and treatment of problems can be the key to preventing loss of vision.

Preparing for eye exams

When a person calls to make an eye appointment, he or she should be prepared to describe any current vision problems. In addition, patients should ask if the eye examination will affect their vision temporarily and if they will need someone to drive them home. They may also want to ask about the cost of the exam, if their insurance plan will cover any of the cost, and how payment is handled.

Before going to the appointment, patients should gather information to help answer questions the eye care professional may ask.

Symptoms of current eye problems (flashes of light, difficulty seeing at night, temporary double vision, loss of vision, etc.).
Eye injuries or eye surgeries (approximate dates, where treated).
Family history of eye problems (glaucoma, macular degeneration, cataracts, etc.).
Any questions about their vision, glasses, contacts, laser surgery, etc.
Prescriptions and over-the-counter drugs currently being used.
Their general health condition (allergies, chronic health problems, operations, etc.).

Patients should also take the following items with them to their eye appointment:

Glasses, contact lenses or both.
Prescription and over-the-counter drugs currently being taken.
Medical or health insurance card.

Signs an eye exam may be needed

A person experiencing any of the following symptoms should schedule an appointment with an eye professional:

Children

Holding a book too close to their eyes.
Difficulty reading the blackboard in school.
Complaints of blurry eyesight.
Squinting a lot.
Closing or covering one eye in order to see.

Adults

Arms are suddenly "too short," i.e., need to hold the newspaper or other reading material far away.
Unusual difficulty adjusting to dark rooms.
Difficulty focusing on close or distant objects.
Unusual sensitivity to light or glare.
Change in the color of the iris.
Red-rimmed, encrusted, or swollen lids.
Recurrent pain in or around the eyes.
Double vision.
Dark spot at the center of their vision.
Lines and straight edges appear wavy or distorted.
Excess tearing or "watery eyes."
Dry eyes with itching or burning.
Seeing spots or ghost-like images.

The following symptoms are indications of serious medical problems that require immediate attention:

Sudden loss of vision in one eye.
Sudden hazy or blurred vision.
Flashes of light or black spots in the field of vision.
Halos or rainbows around lights.
Curtain-like blotting out of vision.
Loss of peripheral (side) vision.

The eye exam

Visual acuity tests measure the smallest object each eye can see at a certain distance. Normally, the eye professional tests a person's eyes by covering one eye at a time and testing each eye separately. It may be necessary to tape a patch over a child's eye to keep him from peeking.

Testing children

In order to test a child thoroughly, the child must participate and cooperate. If children have difficulty with their attention span, they may not test well even though they can see well. If children have developmental impairments or communicate poorly, they may also test poorly.

Tests of visual acuity

The Snellen eye chart is the most familiar chart used to test eyes. It was invented more than one hundred years ago by a Dutch ophthalmologist named Hermann Snellen. It contains letters and numbers that are presented to the patient at a distance of twenty feet.

20/20 vision is normal. If a person has 20/40 vision, they see at twenty feet what a normal eye sees at forty feet. If a person has 20/200 vision, they are legally blind. They only see at twenty feet what a normal eye sees at two hundred feet. If they have 20/15 vision, they see better than normal. They see at twenty feet what the normal eye would have to bring in to fifteen feet to see.

If children don't know their letters, they can be tested with the Tumbling E chart. This chart has Es pointing in different directions and the child points his finger in the same direction the fingers of the E point. Children who are younger than four may have trouble with this test.

Another test that is sometimes used with young children is called the HOTV test. These four letters are projected on the wall one at a time and the child points to the same letter on a card.

Allen pictures may also be used. Familiar shapes are projected on the wall and the child identifies them. This test isn't always accurate because some shapes are easier to recognize than others are. The child needs to become familiar with the test at arm's length before the letters or pictures are projected across the room.

Tests for younger children

If a child is too young to be tested with an eye chart, the eye professional will have to use more primitive tests. First, it will be necessary will get the child's attention with an object such as a light, face, or small toy. Then the examiner will move the object to see how well the child follows the object with its eyes. Preferably the object will be small and far away, but it must be large enough to capture the child's attention. If the child has poor vision in one eye, he or she may not be able to follow the object well. The child may lose interest when the good eye is covered. This type of test is qualitative rather than quantitative.

Comprehensive eye exams

Comprehensive eye exams for adults should consist of the following:

Review of family and personal health history.
Examination of the interior and exterior of the eye for signs of eye disease or general health problems such as diabetes or hardening of the arteries.
Eye pressure and field of vision tests to diagnose glaucoma.
Tests of ability to see sharply and clearly at both close and far distances.
Tests to determine the presence of nearsightedness, farsightedness, astigmatism, depth perception problems, and in people over age 40, presbyopia.
Check of eye coordination and eye muscle function to make sure the eyes are working together as a team.
Test of ability to change focus easily from near to far, and vice versa.

Additional tests for young children should include:

Check for indications of crossed eyes.
Check to ensure the child is using both eyes.
Tests to check eye-hand-foot coordination.
Tests to determine how well the child's vision skills are developing.
Tests to determine normal color vision.

A visit to your eye professional should include a discussion of the exam's findings and any treatment prescribed. It should also include a discussion about maintaining the health of your eyes, eye safety, and good vision on the job.

Talking to your doctor

Most people take an active role in their health care today. An important part of a good relationship with your ophthalmologist (or any doctor) is good communication. Below are some typical questions you may want to ask to get a discussion started.

About your disease or disorder

What is my diagnosis?
What caused my condition?
Can this condition be treated?
How will this condition affect my vision now and in the future?
Should I watch out for any particular symptoms?
Should I call you if these symptoms occur?
Should I make any lifestyle changes?

About your treatment

What is the treatment for my condition?
When will the treatment start and how long will it last?
What are the benefits of this treatment?
How successful is it?
What are the risks and side effects associated with this treatment?
Are there foods, drugs, or activities I should avoid while I'm on this treatment?
If my treatment includes a medication, what should I do if I miss a dose?
Are other treatments available?

About your tests

What kind of tests will I have?
What do you expect to find out from these tests?
When will I know the results?
Do I have to do anything special to prepare for any of the tests?
Do these tests have any side effects or risks?
Will I need more tests later?

It is critical you understand your doctor's responses to your questions. If you don't understand your doctor or are not sure you will remember your doctor's instructions or comments, try one of the following:

Ask questions until you do understand your doctor's comments and instructions.
Take notes, or get a friend or family member to take notes for you.
Bring a tape recorder to help you remember key points of the discussion.
Ask your doctor to write down instructions for you.
Ask your doctor for printed material about your condition.
If you still have trouble understanding your doctor's answers, ask where you can go for more information
Talk to other members of your health care team. Nurses and pharmacists can also be good sources of information.