What is a dilated eye exam?
A dilated eye exam is part of a comprehensive eye exam, in which an eye doctor checks your vision, determines your eyeglasses or contact lens prescription (if needed) and assesses the health of your eyes.
The dilated portion of the eye exam takes place while your pupils are dilated, which allows your eye doctor to get a better look at the retina and optic nerves using magnifying lenses and special light sources.
What happens during a dilated eye exam?
After assessing your visual acuity, your optometrist or ophthalmologist will put a series of drops into your eyes. These drops will stimulate your pupils, making them expand or dilate. Because the drops do not allow the pupils to constrict (get smaller), they provide larger “windows” for your eye doctor to view the back of your eyes.
Most dilating drops take 20 to 30 minutes to reach their full effect. Once your pupils are fully dilated, your eye doctor will assess the health of the back of your eyes with a series of instruments. These tools allow for magnified views of the optic nerves and retina.
Though inconvenient, the process of dilating your pupils is typically painless. After your pupils have been dilated, you may be both sensitive to sunlight and experience blurred vision, mainly when viewing up-close objects.
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Why eye doctors dilate your eyes
During part of the eye exam, your eye doctor will shine a light in your eyes to view the back of your eye and assess your eye health. But because pupils constrict when confronted with light, this does not allow for a full view of the retina and the exam process may be hindered.
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.
The retina, optic nerve and blood vessels lie at the very back of your eye, and all need to be examined routinely for signs of potential health conditions. Clinical signs of conditions such as high blood pressure and diabetes can be noted in the retina and its blood vessels. Dilation enables your eye doctor to conduct a truly thorough examination of your eyes.
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How dilation affects your vision
Your pupils will usually stay dilated for four to six hours, well past the length of your eye exam. This means that you’ll have to navigate the bright outside world while your eyes are still dilated. Some people can have dilated pupils for up to 24 hours after their eye exam. If you are concerned, it is recommended to call your eye doctor.
The dilating drops used inhibit your focusing system, creating blurred vision up close while the pupils remain dilated.
Your large pupils also let in more light, which means you will be more sensitive to bright sunlight. To help tolerate this light sensitivity, it is suggested to bring sunglasses to wear after your appointment. If you forget, your eye doctor can give you disposable polarized sunglasses to take home.
Some patients prefer having someone take them to their eye appointment if the blurry vision and light sensitivity make driving uncomfortable.
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When do I have to get a dilated eye exam?
You may not have to have your pupils dilated during an eye exam. Previously, pupil dilation was simply part of the traditional eye exam, but now, optometrists and ophthalmologists have other options at their disposal. For example, retinal photography can capture images of the retina that in the past could only be viewed with dilation. Your eye doctor can help you decide if this is an option during your appointment.
During a dilated eye exam, your eye doctor can check for signs of these or other eye conditions and diseases:
- Glaucoma
- Diabetic retinopathy
- Cataracts
- Age-related macular degeneration
If you’re at higher risk for developing any of these conditions and diseases, you may be more likely to need a dilated eye exam.
Retinal imaging
Your eye doctor may recommend retinal imaging, which helps them see the back of each eye without dilating your pupils.
These devices use a laser to digitally capture a wide image of your retina. This gives your eye doctor a method to document your eye health. These images may be referenced at future eye health evaluations to monitor progression of many eye conditions and diseases.
Vision insurance does not always cover retinal imaging, so check with your insurance and your eye doctor to determine which option might suit your plan and health needs.
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