How It Is Done continued...
Color vision tests check your
ability to distinguish colors. In the most commonly used color vision test, you
look for different colored numbers or symbols hidden in varying backgrounds of
First, you are shown sample patterns and told what
symbols and numbers you can expect to see. You then sit at a table and cover
one eye. The doctor holds the color test patterns about
14 in. (36 cm) away from you.
Some patterns are harder to pick out than others. As the doctor holds up a pattern, you will identify the number or symbol you see
and trace it using a pointer. Some patterns may not have a number or symbol.
The test is then repeated with the other eye.
How It Feels
You should not feel any discomfort
during these vision tests.
When dilating eyedrops are used
Dilating drops may make your eyes sting and cause a
medicine taste in your mouth. You will have trouble focusing your eyes for
up to 12 hours after your eyes have been dilated. Your distance vision usually
is not affected as much as your near vision, though your eyes may be very
sensitive to light. Do not drive for several hours after your eyes have been
dilated. Wearing sunglasses may make you more comfortable until the effect of
the drops wears off.
In some people, the dilating eyedrops can cause
Vision tests check many different
functions of the eye. Your doctor will let you know if your eyesight is normal or if it is better or worse than normal. He or she may also be able to tell you why you have a vision problem.
Visual acuity testing
The visual acuity score
compares your distance vision with that of people who have normal vision, using
an eye chart. Each eye's score is expressed as two numbers, such as 20/20 (6/6)
or 20/100 (6/30). The first number is the distance you stand from the chart,
usually 20 ft (6 m) when using
a typical wall chart. The second number is the distance from which people with
normal eyesight can read the same line on the eye chart.