24/07/2013
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, your eye
doctor will have you focus on a
small object across the room and
then he or she will cover each of
your eyes alternately while you
stare at the target.
While doing this, your eye doctor
will assess whether the uncovered
eye must move to pick up the
fixation target, which could
indicate strabismus or a more
subtle binocular vision problem
that could cause eye strain or
amblyopia ("lazy eye"). The test is
then repeated up close.
Retinoscopy
Your eye doctor may perform this
test early in the eye exam to obtain
an approximation of your eyeglass
prescription.
In retinoscopy, the room lights will
be dimmed and you will be given a
large target (usually the big "E" on
the chart) to fixate on. As you stare
at the "E," your eye doctor will
shine a light at your eye and flip
lenses in a machine in front of
your eyes.
Based on the way the light reflects
from your eye, your doctor is able
to "ballpark" your prescription —
sometimes right on the money!
This test is especially useful for
children and patients who are
unable to accurately answer the
doctor's questions.
