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What is a dilated eye exam and when do you need one?

dilated eye exam

What is a dilated eye exam? A dilated eye exam is similar to a regular eye exam: Both require you to read an eye chart (so your optometrist can determine your prescription) and have a little light shined in your eyes (so your eye doctor can make sure your eyes are healthy). 

The main difference is that a dilated eye exam takes place while your pupils are dilated, which allows your eye doctor to take a better look at your optic nerves and retinas at the back of your eyes.

SEE RELATED: What to expect during a comprehensive eye exam

What happens during a dilated eye exam?

The process of dilating your pupils is admittedly inconvenient but painless. 

Your optometrist will ask you to tilt your head back so they can place special drops into your eyes. These drops will stimulate your pupils, making them expand or dilate. To get the drops where they need to go, your eye doctor may hold your eyelid open briefly, but don’t worry: They know what they’re doing, and it will be over soon.

Then, you’ll likely have to sit in the waiting room for 20 to 30 minutes while the drops fully dilate your pupils. Finally, your doctor will bring you back and examine your eyes.

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Why eye doctors dilate your eyes

During part of the eye exam, your optometrist will shine a light in your eyes to see if they look healthy. However, pupils retract when confronted with light; the tool that is supposed to help your eye doctor get a better view of your eye often hinders the process. 

Dilating your pupils provides the best of both worlds for your eye doctor: a well-lit view and a large pupil through which to inspect the far reaches of your eye.

Our retinas, optic nerves and a whole bunch of blood vessels lie at the very back of our eyes, and all need to be examined routinely for signs of potential health conditions. Dilation enables your eye doctor to conduct a truly thorough examination of your eyes.

What not to do after eye dilation

Your pupils will stay dilated for several (typically four to six) hours, well past the length of your eye exam. This means that you’ll have to navigate the bright, sunshiny world soon after having your eyes fully dilated, so here’s a list of things not to do after eye dilation.

Drive: After having your pupils dilated, your vision will become blurry and highly susceptible to blinding sunlight, which will make it unsafe for you to operate heavy machinery. Have someone take you to your eye appointment, so you can ensure you have a safe way to get home afterward.

Spend time in the sun: When your pupils dilate, they become especially sensitive to the brightness of the sun and harmful UV rays. Protect your eyes in transit from your appointment by wearing sunglasses, and then spend as little time in the sun as possible until your pupils return to normal.

When do I have to get a dilated eye exam?

You do not have to have your pupils dilated during an eye exam. Dilated eye exams have become less common in the last decade. Previously, pupil dilation was simply part of the traditional eye exam, but now, optometrists are more deliberate. 

It’s increasingly common for eye doctors to only perform this exam if they’re concerned about the potential for eye conditions like glaucoma, diabetic retinopathy, cataracts or age-related macular degeneration. Even in cases where your optometrist suspects there might be an underlying issue at play, there are other options to consider.

Optomap eye exams

The most popular alternative that enables your doctor to inspect your eyes for these same conditions without dilating your pupils: Optomap eye exams. 

Optomap technology uses a laser that digitally captures an image of your retina. This procedure surpasses a dilated eye exam because it’s able to show many different layers of your retina, offering your optometrist a much clearer picture of your eye health. 

The downside is that this option is considerably more expensive than dilated eye exams. If your eye doctor offers Otomap exams, consult with your vision insurance provider to see if this procedure is covered.

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