Pupil Dilation


Dilating eyedrops are used for your own benefit to certify that nothing is left undiscovered during your eye examination.
Most of us are not even aware that our pupils dilate and constrict as light changes around us. The pupil regulates the amount of light that enters the eye
acting similarly to a camera shutter. In the dark
your pupil enlarges to allow more light into your eye. In the light
it decreases in size. Internal muscles contract or relax to control the shape of the crystalline lens
which focuses light rays onto the retina. This is what gives us the ability to see distant objects clearly
and then to immediately change our focus to look at something up close.

In order for your eye care practitioner to carry out a full eye examination
often he/she will have to dilate your pupil with eyedrops. Even though it is absolutely painless
it can still be an annoyance. Many patients often wonder why this needs to be done in the first place.

Your pupil is the door to your entire eye. When it is constricted
there are certain parts of the back of the eye that are impossible to see
like the optic nerve and the retina. Because the doctor shines a bright light in your eye
your pupil is constantly constricted
effectively shutting the door to the back of your eye. Eyedrops dilate your pupil
thus opening up the view for the doctor so he/she can perform a complete examination. Compare this to your physical examination by your family doctor – would you want him/her to just look at you and diagnose something
or would you want them to take a more thorough look? In fact
many systemic diseases
like diabetes
are first discovered during routine eye exams.

Dilating drops work in one of three ways:

  1. They stimulate the iris muscle that opens the pupil
  2. They prevent action of the iris muscle that closes the pupil
  3. They prevent accommodation (adjustment of one’s focus) of the pupil

Drops generally affect vision for two to three hours
and do not typically influence distance vision – though reactions vary from person to person. The third type of eyedrop is usually used on children
since they tend to have exceptional adjustment abilities. If the doctor puts any corrective lens in front of a child’s eyes during an exam
the eyes can actually automatically regulate and focus properly. By putting in the drops
the child’s eyes are prevented from focusing
thus allowing the doctor to discern the proper prescription.

Some tips before your eye exam:

  • Don’t plan any activities (especially those involving crisp eyesight) after your appointment.
  • Bring along some sunglasses for after the appointment. Your eyes will feel sensitive to bright light. Don’t worry if you forget – most clinics supply temporary ones.
  • Bring a friend/family member along to drive you home or arrange for a taxi.

For children who are less than excited about receiving the eyedrops
make sure to reassure them that the effects are temporary. Some brief education about why the drops are needed may also calm them down. Some children might also think it is “cool” to have their pupils dilated
so bring a mirror for them to look at themselves.

Dilating eyedrops are used for your own benefit to certify that nothing is left undiscovered during your eye examination. Should you have any questions/queries/concerns about the drops for your next exam
contact your eye care practitioner.

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