Summary
Pupil dilation is a common method used by eye care professionals to get a better look at the back of your eye. It can help them more accurately detect and monitor conditions such as macular degeneration, glaucoma, diabetic retinopathy and more. Special eye drops will be used to dilate your pupils, which may take up to 30 minutes to work and last several hours after your appointment. Bringing sunglasses is recommended, as your eyes may be more sensitive to bright light.
Why do I need my pupils dilated for an eye test?
When your pupils are dilated (also known as mydriasis), they expand, which makes it easier for your eye care professional to examine the back of your eye, including your retina and optic nerve. Using examinations such as OCT, fundus photography and retinoscopy, your eye care professional can detect or monitor conditions such as macular degeneration, glaucoma, diabetic retinopathy, and retinal tears or detachment. Some of these conditions can have little or no symptoms in their initial stages, so dilation can be a valuable tool for early detection.
Your eye care professional may not need to check dilate your eyes during every appointment. There are several factors they might consider to determine whether to dilate your eyes, which may include:
- Your age. People over 60 may need more frequent exams with dilation.
- Your pupil size. If your pupils are naturally small, it can be harder to get a clear view of the back of the eye without dilation.
- Any pre-existing eye conditions or risk of developing an eye condition.
- Any recent changes in your vision.
How are pupils dilated?
Your eye care professional will dilate (enlarge) your pupils using special eye drops. There are different types of drops which can be used for dilation, your eye care professional will select the best type for you and your eyes.
After the drops have been put in your eyes, it takes between 15 and 30 minutes for them to fully dilate your eyes.
Are there side effects of dilation?
Most people experience light sensitivity, blurry vision and difficulty focusing up close after dilation. These effects are temporary and typically resolve as the drops wear off. Some people also report an initial stinging sensation or mild discomfort when the drops are first applied.
These side effects mean you won’t be able to drive home after your appointment. If you are likely to have your eyes dilated during your appointment, it’s a good idea to arrange a lift home afterwards or plan to catch public transport. It’s also recommended to bring a pair of sunglasses as they can make you more comfortable with light sensitivity.
Further side effects from dilating eye drops are uncommon, but their risk will vary depending on the type of drop and your medical history. Your eye care professional will be able to discuss any risks specific to you and the drops they are using.
How long does dilation last?
The exact time pupil dilation will last differs from person to person. Many people find the effects of the drops, including blurry vision or light sensitivity, wear off after four to eight hours. However, for some people it can take as long as 24 hours.
Speak to your eye care professional if you have concerns about the duration of your pupil dilation or any side effects.
Natural pupil dilation
Pupils can also dilate naturally in everyday life, in response to dim lighting, strong emotions or excitement, adrenaline, or certain medications. They usually return to their normal size on their own, though how quickly depends on the cause. If you’re ever concerned about your pupils for any reason, it’s best to talk to your doctor.
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