Your Routine Eye Exam
Visual acuity tests measure the smallest object each eye can see at a certain distance. Normally, each eye will be done individually by covering one eye at a time. It may be necessary to tape a patch over a child’s eye to keep him from peeking. The use of the Snellen chart is the most common way to test visual acuity. This chart contains letters and numbers that decrease in size. When taking the test, the distance between the patient and the chart is 20 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.
For children that do not know letters and numbers, they can be tested with the Tumbling E chart. To take this test, the child points his/her finger in the same direction as the E is pointing. Children who are younger than four may have trouble with this test, so there are several different tests that can be used to obtain a child’s accurate visual acuity.
Comprehensive Eye Exams
Comprehensive eye exams for adults include 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 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.
Refraction: part of a routine eye examination is a refraction. This test tells the doctor exactly what prescription may be needed if glasses or contacts are required. The test is performed by having the patient look through a device (called a phoroptor or refractor) and focus on an eye chart 20 feet away to help determine the prescription that allows the patient to see clearly.
Your visit to Heaton Eye Associates will include a discussion of the exam’s findings and any treatment prescribed.