What Is Eye Dilation?
Eye dilation is used during an eye exam to give your doctor a closer look at your optic nerve (which connects your eye to your brain) and your retina (a layer of cells in the back of your eye). This helps them check your overall eye health and catch any potential issues early, before they become serious.
When dilating your eyes, your doctor will apply eye drops to widen the pupil — this opens a clearer view of the inner parts of your eye. It's a simple exam with little to no discomfort.
Even if your eyes feel healthy, it's important to get a dilated eye exam, as many eye diseases can show no obvious warning signs.
Dilated Eyes vs. Normal Eyes
Your eyes dilate when the black centers of your eyes (pupils) appear larger than normal. This natural process happens due to changes in lighting: in a bright room, your pupils shrink in size to block out light, while in a dark room, they expand (dilate) to let more light in.
For size reference, a dilated pupil in dim lighting is 4-8 millimeters, while a normal, undilated pupil is 2-4 millimeters in bright lighting. The size of your pupils is controlled by tiny muscles from the colored part of your eye, called the iris.
Why Do They Dilate Your Eyes?
Your eye doctor needs to dilate your pupils in order to see the inside of your eye. The eye drops used for dilation cause your pupils to widen, stopping them from shrinking, while the doctor shines a light in your eyes.
It helps your doctor to spot symptoms of common eye conditions and diseases. They can also look for issues like a torn or detached retina.
Dilated eye exams can diagnose:
Diabetic retinopathy. A condition that can develop in people with type 1 or 2 diabetes and may lead to blindness. Your doctor looks for blood vessel damage in your retina. If you have diabetes, it is best to schedule a yearly dilated eye exam with your doctor to prevent vision loss.
Glaucoma. A group of eye conditions that result in damage to your optic nerve. Your doctor will use eye drops to dilate your eyes and a special tool to check for any damage to your retina and optic nerve.
Age-related macular degeneration (AMD). An eye condition that affects your central vision, caused by aging and damage to the macular, the part of your eye responsible for sharp, straight-ahead eyesight. Your doctor will dilate your eyes and check for AMD in the retina.
Cataract. A clouding of the lens of your eyes. After dilating your eyes, your doctor will look at your retina and use a device called an ophthalmoscope to check for cataracts.
By dilating your eyes, your doctor is able to catch problems before they become more serious and cause symptoms like vision loss. This can allow for early intervention and better protection of your eyesight.
How Do They Dilate Eyes?
Your eye doctor will apply a small amount of medicated eye drops to each eye. These drops widen your pupils and relax the iris, the colored part of your eye that controls the size of the pupil. This means it can temporarily stay open in brighter light while you're doctor examines your eye.
How long does it take to dilate eyes?
It generally takes 15-30 minutes for your pupils to fully dilate. Eyes with lighter colors such as green, blue, or hazel tend to dilate faster than brown eyes.
How long do eyes stay dilated?
Most people are back to normal within about four to six hours. But for you, the effects could wear off more quickly, or they could last much longer. Certain strengths of dilating drops may last longer than others.
Can I Drive After They Dilate My Eyes?
Dilation can temporarily cause blurry vision. And 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 decide to drive after being dilated, drive cautiously because it can raise the risk of a car accident.
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. If you're in doubt, ask your eye doctor for their recommendation based on your specific case.
Whether you get behind the wheel, it's a good idea to bring sunglasses with you so you can shield your eyes after the exam.
Can I Work After Eye Dilation?
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.
How Often Do I Need It?
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.
The National Eye Institute recommends everyone older than 60 years have a dilated exam every one to two years. If you're African American, you're at a higher risk of glaucoma, so this recommendation starts at age 40. You're also at a higher risk if anyone in your family has had it. 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.
Side Effects of Eye Dilation
After you get a dilated eye exam, you may experience symptoms, including:
- Blurred vision
- Light sensitivity
- Headaches
- Difficulty focusing on close objects
- Allergic reactions
When Not to Dilate Eyes
It's important to follow your eye doctor's recommendations for having your eyes dilated to prevent eye diseases. However, there are a few instances in which you may need to avoid dilation:
- If you have a sensitivity or allergy to the eye drops used for dilation
- If you have an eye injury
- If you have had a head injury that caused pupil dilation
Always talk with your doctor before deciding to skip dilation. They can tell you whether there is cause for worry.
Can You Refuse Eye Dilation?
Yes, you can refuse eye dilation during an eye exam. However, it is highly recommended that you don't, as it can prevent eye diseases.
Takeaways
Dilated eye exams help your doctor to find problems like glaucoma, diabetic retinopathy, and cataracts early. While it may cause temporary symptoms like blurry vision and sensitivity to light, it's important for checking your eye health, especially as you get older or have health factors such as diabetes. If you have concerns like eye sensitivity or allergies, talk with your doctor to find the best approach for your eye exam.
Dilate Eyes FAQs
What happens if your eyes don't dilate?
If your pupils don't dilate, it could be a sign of a problem with your eyes. You may have a condition called miosis, in which the pupils stay smaller than normal and don't react to light changes. Many of the causes of miosis are serious and require medical treatment.
Is eye dilation painful?
No, the eye dilation exam itself should not cause you any pain. But the eye drops may cause a slight sting to your eyes after being applied, though the feeling should only last a few moments.
Do eyes dilate when in love?
Yes, your eyes can dilate when you're in love. This reaction is caused by oxytocin — a hormone that is released during moments of attraction or arousal.
