How Long Do Pupils Remain Dilated After an Eye Exam?

Dilating the pupils of the eyes helps an ophthalmologist view the internal structures, including the lens, optic nerve, blood vessels, and retina. Dilation involves the use of special eye drops that either stimulate contraction of the muscles surrounding the pupil or relaxes the muscles so that they open.

Eye drops
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Dilation is a key component of a comprehensive eye exam, allowing doctors to identify and diagnose eye problems that they may otherwise not see. The National Eye Institute currently recommends that adults regularly undergo such exams starting at age 40 to 60.

Understanding the Pupil

The pupil is similar to a camera aperture in that it becomes bigger or smaller, depending on how much light is needed. To do this, the pupil will undergo miosis, in which the constriction of the pupil causes it to close, or mydriasis, in which the dilation of the pupil allows it to open.

The pupil size is controlled by both the sympathetic nervous system (the "fight or flight" response) and the parasympathetic nervous system (the converse response in which the body slows high energy functions).

The pupil size can change for many reasons. It could adjust in response to the amount of light it is exposed to. It can also change when a person becomes excited such as in moments of physical stress, emotional stress, or exposure to painful stimuli.

It is believed the "fight or flight" response is an evolutionary one, allowing more light into the eye so that the body can react more readily to potential harms.

Common Duration of Pupil Dilation

Dilating the eyes is a central part of an eye exam. It involves the administration of two or three drops directly into the eye. Depending on what the doctor is trying to achieve and how large the pupil needs to be, different types of eye drops may be used, including:

  • Phenylephrine
  • Tropicamide
  • Hydroxyamphetamine
  • Cyclopentolate
  • Atropine

Eye drops are placed in both eyes so that the retina, macula, and optic nerve can be examined closely using a handheld light and magnifying lens. While the dilation itself is not painful, it can be incredibly uncomfortable as the eye has no means by which to protect itself from light.

After a dilated eye exam, your pupils will normally remain open for about three to four hours, sometimes longer.

The time eyes remain dilated varies according to the type of drops used, as well as the color of your eyes. By and large, dark-colored eyes have shorter dilation periods, typically for two to four hours, while light-colored eyes may stay open for up to eight hours.

Children, meanwhile, are often dilated with stronger drops to improve the accuracy of the exam. It is not uncommon for some kids to wake up the morning after an exam with their pupils still wide open.

In the past, a medication called Rev-Eyes (dapiprozole) was used to reverse dilation. It is now off the market. When it was available, typically it would take one to two hours for the medication to have an effect. There were other side effects with the medication, and given the cost and side effect profile, these drops are no longer administered.

Coping With Dilation

For most people, the side effects of dilation are bothersome but not intolerable. To deal with blurred vision and sensitivity to light, disposable sunglasses are usually provided to help reduce short-term discomfort. Unlike regular sunglasses, these block off peripheral light from the side of the lenses as well as the front.

Uncommon Duration of Pupil Dilation

Most, but not all, drops cause a side effect called cycloplegia. Cycloplegia is the temporary paralysis of the muscle which allows the eye to focus on near objects. In some people, this effect can last for hours. In others, it may take several days for the vision to fully normalize.

There are situations in which a doctor will want to intentionally cause cycloplegia. One such example is in young children whose focusing mechanism is so strong that it is often difficult to measure their vision or refractive error.

Cycloplegic drops may also be used to treat eye diseases or trauma that cause acute pain and light sensitivity. One such condition is called uveitis, the inflammation of the middle layer of the eye (uvea).

In some cases, the duration of pupillary dilation can significantly vary from the norm. This may be due to some inherent super-sensitivity your eye may have to dilating medication. Some medications for dilation that can be used may last for days if not a week or more.

Pediatric eye doctors may also use them to treat a condition called lazy eye in which a child develops reduced vision for any number of reasons. These types of drops are prescribed for much longer periods of time, up to several months in some cases.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Eye Institute. Get a dilated eye exam.

  2. Sani RY, Hassan S, Habib SG, Ifeanyichukwu EP. Cycloplegic effect of atropine compared with cyclopentolate-tropicamide combination in children with hypermetropiaNiger Med J. 2016;57(3):173-177. doi:10.4103/0300-1652.184065

  3. Agrawal RV, Murthy S, Sangwan V, Biswas J. Current approach in diagnosis and management of anterior uveitisIndian J Ophthalmol. 2010;58(1):11-19. doi:10.4103/0301-4738.58468

By Troy Bedinghaus, OD
Troy L. Bedinghaus, OD, board-certified optometric physician, owns Lakewood Family Eye Care in Florida. He is an active member of the American Optometric Association.