When do eyes dilate

Once your eyes are dilated, there is an increase in light sensitivity because the pupil is large and more light is coming through, so bring your sunglasses , or your ophthalmologist may provide some disposable shades for your use. You may also experience blurry vision, particularly if you are trying to read. If it is your first time having your eyes dilated or you know your vision is too impaired for driving after dilation, bring a friend or companion to drive you home from your examination.

While in the past there were some eye drops that could reverse the dilation, these are no longer available, so you will have to wait the hours before the drops completely wear off. The optic nerve can be seen through an undilated pupil, but for optimum viewing a dilated pupil is required.

This is important for the diagnosis of glaucoma , as well as other diseases of the optic nerve. Learn about what to expect during a glaucoma eye exam. Two very common retinal diseases, diabetic retinopathy and age-related macular degeneration AMD , are diagnosed and monitored by examining the retina through a dilated pupil.

Learn about what to expect during a macular degeneration eye exam. In addition to macular degeneration and glaucoma, there are many other conditions that require pupil dilation, such as detection of a retinal tear or detachment, or an ocular tumor, just to name a few. As part of a comprehensive eye examination, pupil dilation is very important at revealing the status of your optic nerve and retina, and is critical to preventing and treating eye conditions that could potentially lead to vision loss.

Yvonne Ou, MD, is a board certified ophthalmologist who specializes in glaucoma, including medical, laser and surgical therapies; cataract evaluation and treatment including combined cataract and glaucoma surgery; glaucoma filtering and implant surgery; and newer procedures. Back to Expert Advice. Once your doctor puts in the dilating drops, it takes about 20—30 minutes for your pupils to fully open, or dilate. After your eyes are fully dilated, the effects will last for four to six hours for most people.

Some people feel the effects of dilating drops for longer, including people with lighter color eyes. Dilation in children can last up to a full day after the exam. The important thing is to use caution as long as your vision is blurry or your eyes are light sensitive. Dilation is harmless in the long term, but it does come with short-term side effects.

These will usually last for about four to six hours. Dilation allows an eye doctor to look inside your eyes. The widened pupil allows your doctor to use a magnifying lens to look inside your eye and at the back of your eye. It also helps diagnose some chronic conditions that affect more than your eye, such as high blood pressure and diabetes. This is because those conditions can lead to changes in the eye.

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Related Articles. What Is Mydriasis Dilated Pupils? What Is Central Vision Loss? What Is Traumatic Iritis? Ciliary Ganglion: Anatomy, Function, and Treatment. What's the Reason for Your Eye's Pupil? Blurry Vision in One Eye. In bright light, your pupils constrict get smaller to prevent too much light from entering your eyes. In dim lighting, your pupils dilate get larger to allow more light in. Normal pupil size generally ranges from 2.

To some degree, pupil size tends to get smaller with age. In one study of Americans ages 18 to 34 years, average pupil sizes in three different lighting conditions were found to be:. A dilated pupil can sometimes still react to light — that is, get smaller in bright light or when a light is shined at the eye. A large pupil that is completely unresponsive to light is called a "fixed" dilated pupil. Dilated pupils aren't the same as anisocoria , a common condition where both pupils react normally to light but differ in size by about a half-millimeter or more.

The following prescription and non-prescription medicines can cause your pupils to dilate and affect their ability to react to light:.

Atropine used for myopia control and other medical purposes. A serious, penetrating eye injury can damage your iris and cause the pupil to become dilated and irregular in shape. Sometimes, this sort of injury can occur during an eye surgery, such as a complicated cataract surgery or a corneal transplant. A head injury , stroke or brain tumor can affect how your pupils react to light and cause dilated pupils. One or both eyes may be affected.

This is why you see physicians checking an athlete's pupils with a penlight following head trauma sustained during sporting events, or when a patient arrives at a hospital emergency department with other possible stroke symptoms.

Research has shown that alcohol and marijuana — separately or in combination — can reduce your eyes' ability to recover from exposure to a bright light source such as oncoming headlights at night and adapt to changing light conditions. This effect can last two hours or longer after drug ingestion.