Why Do I Need to Get My Eyes Dilated?

Medically Reviewed by Whitney Seltman, OD on April 10, 2023
3 min read

Dilation is part of a thorough eye exam. You may think it’s a hassle. But it gives your doctor a good look inside your eye. It’s especially important if you’re having eye pain or vision problems, or if you’re more likely to get certain eye diseases.

Normally, your pupil gets smaller when light shines into it. In dilation, your doctor uses special eye drops to force the pupil to stay open. This allows them to see much more of the back of your eye, including the entire retina, the part of the retina called the macula, and the optic nerve.

During a dilated exam, your doctor can spot problems like a torn or detached retina or an eye tumor. They can also diagnose and monitor common eye diseases that can take away your sight:

  • Diabetic retinopathy: Signs include blood vessels that leak, swell, or grow abnormally in the retina.
  • Glaucoma: Your doctor looks for damage to the optic nerve.
  • Age-related macular degeneration: Protein or pigment buildup and unusual growth of blood vessels are symptoms of a breakdown of the macula.
  • Cataract: A clouding of your natural lens.

Almost all of these conditions are painless, so you may not even know you have one unless you see your doctor and have your eyes dilated.  

Everyone’s eyes react differently to the dilation drops. It usually takes 15 to 30 minutes for your pupils to open completely. Most people are back to normal within about 4 to 6 hours. But for you, the effects could wear off more quickly, or they could last much longer. Certain strengths of dilating drops may lost longer than others.

Dilation doesn’t typically affect your distance vision, unless you are farsighted and don’t have glasses to correct your vision. But because your pupils can’t control the amount of light going into your eyes, the glare outside may bother you. For some people, that makes it unsafe to drive.

If you’ve never had your eyes dilated, get someone else to drive you home from your appointment. Once you’ve had it done, you’ll know whether dilation means you can’t drive after an exam.

Whether or not you get behind the wheel, it’s a good idea to bring sunglasses with you so you can shield your eyes after the exam.

Dilating drops make it hard for your eyes to focus on things close to you. You probably won’t be able to read, use the computer, or do other tasks that require near vision after your appointment, unless you wear bifocals or use reading glasses. If you work outside, the bright light may bother you. It may be easier to make an appointment later in the day so you don’t have to go back to work.

The National Eye Institute recommends everyone over 60 have a dilated exam once a year. If you’re African-American, you’re at higher risk for glaucoma, so the yearly recommendation starts at age 40. If you have diabetes, you should also have a dilated exam once a year no matter how old you are.

Dilation is often a normal part of an eye exam for people who wear glasses or contacts. But if you’re young and your eyes are healthy, you may not need it every time. Your doctor also may be able to use other methods to check your retina without dilating your eyes, but they may not work as well. See what your doctor recommends.

Many eye diseases are more common as you get older. The American Academy of Ophthalmology says everyone should get a baseline exam with dilation when they’re 40. That way, your doctor can track any changes that could signal a problem.