Is Dilating My Eyes Necessary?

Is Dilating My Eyes Necessary? 

Blue eye with dilated pupil

If you have read any of our previous blogs, you probably know that visiting your eye doctor for an annual eye exam is an essential step towards keeping your eyes and vision healthy. You may also know that during this exam your eyes will be dilated. While dilation is not painful, it can be inconvenient and even a bit uncomfortable. This may lead you to wonder: Is dilation really necessary? In this blog, we’ll discuss what happens when your eyes are dilated and why this procedure is an essential and necessary part of your annual eye exam. 

What is Dilation?

Eye dilation is the process of using medication to expand the pupil of the eye. This process allows more light to enter the eye, so your eye doctor can see into the back of the eye. During an eye exam, your eye doctor or technician will dilate your eyes by instilling one or two drops of medication into your eyes. There are 2 main types of dilating drops. One works by causing the muscles of the iris to constrict, making the opening in the iris (the pupil) larger. The other works by preventing the pupil from reacting when exposed to light, allowing more light to enter the eye and providing a wider view of the inside. This drop also relaxes the muscle that controls the eye’s ability to focus, making vision blurry. 

Dilation is most commonly used during an eye exam, but it does have therapeutic uses as well. In children, long term dilation may be used to treat amblyopia (lazy eye) in children. Dilation may also be used to treat inflammation and degenerative myopia. 

There are several medications used to dilate the eyes. Common dilating drops include:

  • Tropicamide
  • Phenylephrine
  • Atropine
  • Cyclopentolate
  • Hydroxyamphetamine

Infographic of dilated pupil

National Institute of Health National Eye Institute

Why Do I Need To Be Dilated?

Many eye problems occur in the back of the eye. Your doctor needs the widest, clearest view possible in order to find these problems. Common eye problems found during a dilated eye exam include:

  • Retinal detachment
  • Diabetic Retinopathy
  • Age Related Macular Degeneration
  • Glaucoma
  • Stroke
  • Hypertension

Without dilation, it would be difficult or impossible to diagnose or manage these conditions. The opening of the eye is not wide enough to give your doctor an adequate view, and the pupil naturally constricts when exposed to bright light. Because the dilating drops prevent this constriction, the doctor is able to get a clear view of the internal structures of the eye. 

Side Effects of Dilation

Dilation does have several common side effects. These include:

  • Blurry vision
  • Inability to see up close
  • Sensitivity to light
  • Stinging or burning immediately after drops are placed in eye
  • Headaches

Dilation used for eye exams typically wears off after 4-6 hours, but may last up to 24 hours. Light colored eyes may stay dilated longer than dark eyes. In sensitive individuals, such as children, eyes may stay dilated for 24 hours or longer.

Some individuals may have a more serious reaction to dilation. This usually occurs in individuals who are allergic to the dilating medication. The most common reactions are redness and swelling of the eyes. More serious reactions can include dry mouth, rapid pulse, flushing in the face, and fever. 

How to Prepare

If you know you are having your eyes dilated at your eye exam, there are a few steps you can take to prepare:

  • Bring sunglasses. They will help to minimize light sensitivity.
  • Bring reading glasses if you have them. Wearing reading glasses will help you to see up close while your eyes are dilated. 
  • Have someone drive you. Because dilating drops will make your distance vision blurry. you may feel more comfortable having someone else drive while you are dilated. If you feel that you can see clearly you may drive yourself. Every patient feels differently about this, and it is up to you to decide. 
  • Try to come in on a day off, or after work. You may have a hard time returning to work, especially if you do a lot of reading or computer work.

While sometimes inconvenient, dilation is a very necessary tool to help keep your eyes and vision healthy. Being prepared for dilation can minimize the side effects and make you feel more comfortable while your eyes are dilated. To schedule an eye exam, please call or text (907) 328-2920. To learn more about your eyes, you can read all of our blog entries on our website at


National Institute of Health National Eye Institute, Get a Dilated Eye Exam,

Written by: Gina Stafford COA, LDO, ABOC

Posted in: Eye Doctor in Alaska, Eye Health Guide

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