Optometrist diopter with girl.

In this eye exam, a doctor dilates your eyes to check for problems that can be complications of diabetes. Here’s what to expect during a dilated eye exam.

Your eyes may be a “window to your soul,” according to Shakespeare, but medical experts today know they can be a window to your health if you have type 2 diabetes.

Eye doctors use a dilated eye exam to check your eye health. People with diabetes in particular need this exam each year to detect early signs of diabetes-related eye problems, according to the American Diabetes Association (ADA). The most common eye complication from diabetes is diabetic retinopathy, which is damage to the blood vessels in the retina that can cause blurred vision or even blindness. People with diabetes are also more likely than people without diabetes to develop cataracts and glaucoma, the ADA reports.

A dilated eye exam is part of a comprehensive eye exam, says Natasha Herz, MD, an ophthalmologist in Kensington, Maryland, and a spokesperson for the American Academy of Ophthalmology (AAO). A comprehensive eye exam may also include a visual acuity test, a visual field test, and refraction assessment, among other tests. During the dilated eye exam your doctor will put special drops in your eyes to dilate them, which means enlarging the pupils. This allows your doctor to see the optic nerve, blood vessels, retina, and macula, the cells in the center of the retina, Dr. Herz says. “If there’s a problem, such as damage from diabetes, this is where your doctor would see it.”

What You Need to Know

You might see three types of eye healthcare specialists if you have diabetes, but not all of them do dilated eye exams, according to the American Association for Pediatric Ophthalmology and Strabismus. These eye specialists may include:

Ophthalmologists. These are medical doctors who focus on eye health. They can do a dilated exam, find signs of diabetes damage in the eye (as well as other eye conditions), and prescribe treatment.

Optometrists. These are eye professionals who focus on changes in vision and corrective lenses. They can also do a dilated eye exam and find signs of diabetes damage, but they can’t treat it. They’ll refer you to an ophthalmologist for treatment.

Opticians. These are eye professionals who fit corrective lenses. They don’t perform dilated eye exams.
You don’t need to do much to prepare for a comprehensive eye exam, even one that includes a dilated exam, but there are a few things you should bring:

Your list of medications. Write it down or keep it on your smartphone. Be sure to include all vitamins, supplements, and over-the-counter medications you take.

Your blood sugar numbers. An ophthalmologist will find your A1C and recent blood sugar numbers important for assessing your eye health. Herz says that these numbers are significant to an eye doctor whether you’re meeting your diabetes treatment goals or not.

Your glasses. “People often want to know if their prescription has changed,” Herz says. Your glasses can be assessed to determine your current prescription.

It might also be wise to take sunglasses because you may want them when you leave your doctor’s office. Some eye drops that dilate the eyes take two to four hours to wear off, Herz says. Stronger ones might take longer. Until then, your eyes might feel irritated or teary, and they’ll be sensitive to light.

The drops affect your close-up vision more than your long-distance vision, so it’s OK to drive, but you’ll need to wear sunglasses to do so, Herz says. Reading and writing aren’t recommended until the drops wear off. The exception, she says, are people who have bifocals because the magnifying lenses can help them.

After a Dilated Eye Exam: What’s Next?

Once you’ve had a dilated eye exam, plan on having one each year — or more often if your doctor finds signs of damage from diabetes. Depending on the results of your dilated eye exam, you might also need to come back for glasses, more tests, or treatments.

“It’s important to know that many eye diseases and conditions don’t have noticeable signs or symptoms,” Herz says. “If you wait until you see warning signs or vision changes, you might already have eye damage. It’s a good idea to get your comprehensive eye exam even if you feel well.” Early diagnosis and treatment of eye problems can help maintain eye health and protect your vision.

To see what else you might expect for a dilated eye exam, please visit EverydayHealth.com.