Eye dilation: What you need to know

When your eyes are dilated, your pupils (the black part of each eye), gets bigger. It is normal for your pupils to change size depending on how much light is around you. The pupils of your eyes naturally get smaller in bright light and bigger in low light, which lets more light into the eye and helps you see better in a dark environment. 

But your clinician may also use special eye drops to dilate your eyes during an exam. These eye drops affect the muscles in the iris (the colored part of the eye) causing the pupils to expand. When your eyes are dilated, the clinician can see the inside of your eye more clearly. 

Eye dilation lets your clinician get a better look inside your eyes. When your pupils are dilated, your clinician can see a significantly larger portion of the retina — the light-sensitive tissue at the back of the eye — than they could without dilation. This can help them detect retinal problems and early signs of eye diseases such as glaucoma, macular degeneration, or diabetic retinopathy that might not otherwise be noticeable.

• A slightly longer appointment: After your clinician puts the drops in your eyes, you’ll need to wait up to 30 minutes for your eyes to dilate fully. Only then can the clinician do the exam.
• Blurry vision: Your vision will probably seem blurry for about three hours following eye dilation. Close work, like reading or computer-based tasks, will likely not be possible during this time.
• Light sensitivity: When your eyes are dilated, bright lights may feel uncomfortable, mainly outdoors. Bring sunglasses if you have them; if not, we’ll give you a pair.
• Transportation concerns: Think about how you will get home after your appointment, especially if you have never had your eyes dilated in the past. If your vision is blurry, you might not be comfortable driving, biking, or riding a scooter.

You should expect to have your eyes dilated if you:

• Have never previously been dilated or if this is your first appointment.
• Have diabetes.
• Have just started experiencing flashes of light in your eyes, floating spots, or a sudden change in your vision.
• Have recently been hit in the eye.
• Have previously been diagnosed with, or treated for, any condition or disease affecting your retina. This would include such conditions as retinal detachment, macular degeneration, or damage to the retina due to diabetes (diabetic retinopathy).
• Are severely nearsighted.
• Are 60 years old or older. You should expect to be dilated every two to three years after age 60, even if you don’t have symptoms.