Eye Health - Why is Pupil Dilation Important For an Eye Examination?

A woman from Puerto Rico recently asked meyou are developing an eye disease. The earlier
why her eye doctor administers drops to dilatethat I am able to detect this, the better the
her pupils during an examination. She mentionedoutcome will be for your overall eye health.
that she found this to be very annoying becauseBecause the eye is such a sensitive structure, it
in Puerto Rico there is a lot of sun and, when shealso can show early signs of other disease
went outside after her appointment, the lightconditions, such as high blood pressure
made her eyes hurt.(hypertension), diabetes, and elevated cholesterol
This is a very important question and is one about(hypercholesterolemia). Pupil dilation can help me to
which I am sure that many other people haveidentify these problems early. However, there are
wondered.certain conditions for which pupil dilation is not
So... is pupil dilation really necessary?recommended. Foremost among these is primary
Yes. As an eye-care professional, I have a dualangle-closure glaucoma. In this condition, the angle
responsibility: to ensure that you have the bestformed by the iris and the cornea in the front
visual acuity possible and to monitor your eyepart of the eye, known as the irideocorneal angle,
health. It is the second of these, monitoring eyeis narrow. This can impede the normal flow of
health that requires administration of eye drops tofluid, known as aqueous humor, in this region and
dilate your pupils. The misunderstanding occursrapidly raise the pressure inside your eye. Dilating
because most people visiting an eye doctor arepupils in eyes that already have narrow
focused on the visual acuity aspect. Since pupilirideocorneal angles can cause the angles to
dilation is not needed to test visual acuity, it oftennarrow further and result in a pupillary block,
is considered an unnecessary nuisance. However,which is a medical emergency.
as you soon will see, this is an indispensable toolFollowing an eye examination, your pupils typically
that helps me to monitor the health of your eyes.will remain dilated for 3-4 hours. During this time,
I perform pupil dilation for an eye examinationyou will experience sensitivity to light and may
because doing so enables me to get the best lookhave blurry vision, especially during reading and
at the back of your eye. In technical terms, thisother work requiring close focus. For this reason, I
area is called the vitreous chamber. It is filled withalways recommend that my patients bring
a fluid called vitreous humor. The process usuallysunglasses with them so that they are not
involves administering two classes of eye drops:bothered by light when they go outside. I provide
numbing drops followed by two different types ofdisposable sunglasses to patients that have
dilating drops.forgotten to bring their own, but these resemble
Widening (dilating) a patients' pupils increases thethe 3-D glasses that are given out at movie
angle in which I can observe the back of the eye.theaters and are not particularly stylish.
I examine this area by pointing a beam of lightAs you can see, the benefits of pupil dilation for
through the pupil. Normally, in the presence ofmonitoring eye health far outweigh any
bright light, the pupils constrict to allow less light toshort-term inconveniences. Most of these can be
pass through to the retina. This would create aneffectively managed, such as temporary
unacceptable situation in which I only would besensitivity to light with sunglasses.
able to see a small point in the back of your eye.Under no circumstances should you attempt to
However, with the pupils dilated, I am able to seedrive an automobile after an eye examination in
a much greater area and have a clearer view ofwhich your pupils have been dilated. If public
this region.transportation is unavailable, I recommend that
Once I have administered eye drops for pupilyou arrange to have someone able to drive either
dilation, I examine the optic nerve and the bloodaccompany you to the exam or be available to
vessels in your retina. Specifically, I look forpick you up when it is finished. Similarly, if you plan
changes in the optic nerve that could be anto go to work after the examination, you should
indication of glaucoma or other eye healthnot operate any machinery or do other work that
problems, such as macular degeneration. I alsorequires fine focus.
evaluate the quality of the blood vessels, includingPersons over 50 years of age that have diabetes,
the way that they cross each other. Changes inhigh blood pressure, and/or elevated cholesterol
the optic nerve, retina, or blood vessels from oneshould have yearly eye examinations in which
eye examination to the next could be a sign thattheir pupils are dilated.