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Have you ever wondered why your eyes must be
dilated for an exam? Find out why it’s so important.
Do you think of getting your eyes dilated as a
nuisance? We’ll be the first to admit that even though it’s painless,
dilating your eyes is probably annoying at best. Maybe
you’ve never really understood just what we’re accomplishing by putting
those pesky drops in your eyes. Here’s your chance to find out.
Your eye exam begins with a thorough
investigation of the lids, lashes, conjunctiva, sclera and cornea – the
external surfaces. Using a microscope and a bright light, the doctor will
move in for a closer look at the anterior chamber, iris and crystalline lens.
The iris is very similar to the shutter of a camera. When you take a
picture on a bright sunny day, the shutter becomes smaller, allowing less light
to enter. Likewise, your pupil becomes smaller when we shine a bright
light at your eye, making it very difficult to peer inside. That’s where
the dilating drops come in.
Dilating drops work on one of two principles:
they either stimulate the iris muscle that opens the pupil (the dilator), or
prevent action of the iris muscle that closes the pupil (the sphincter).
After the drops take effect, your doctor can get a much better view of your
retina, optic nerve and vessels in the back of the eye. This is a very
important part of your preventative eye care as well as some eye surgeries.
From this simple step, we are able to gather a lot of important information
about your eyes. In fact, some systemic diseases such as hypertension and
diabetes are first discovered during the dilated eye exam.
Some dilating drops also prevent accommodation.
The natural lens is able to accommodate or adjust the eye’s focus until about
the age of 40. Children and young adults are especially good at this, and
their ability to accommodate sometimes prevents the doctor from getting an
accurate refraction for glasses. That’s why young eyes are often dilated
for a “wet” refraction so the doctor can get a true picture of what the
child’s prescription really is.
There are a few things you can do to make your
visit a bit more comfortable:
- Don’t
plan any activities after your appointment that require crisp vision.
(Plan to read the stock market page another time.)
- Bring
along a pair of dark sunglasses for the ride home. Don’t worry if
you forget yours, just ask for a disposable pair as you check out.
- If
you know you’ll have trouble seeing to drive home (even with the
sunglasses), please bring a friend.
- Bring
a newspaper, book or magazine with larger print to read after the drops
begin to work.
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