Eye dilation refers to a widening of the pupils. When doctors dilate the pupils during an eye exam, it typically lasts between 4 and 24 hours.
Doctors sometimes use eye dilation drops to dilate a person’s pupils. This allows the doctor to see into the back of the eye, which is useful for diagnosing certain eye conditions.
Eye dilation takes time, and most eye drops will need up to 30 minutes to fully dilate the eyes. Eye dilation generally lasts between 4 and 24 hours. This margin is wide because certain factors significantly affect the duration of eye dilation.
Read on to learn more about the factors that help indicate how long eye dilation will last. This article also looks at the potential side effects of eye dilation drops and how to manage them.
Before the eye dilation test begins, the eye doctor — either an ophthalmologist or an optometrist — will administer the dilating eye drops.
According to the American Academy of Ophthalmology, eye dilation then takes effect within 20 to 30 minutes. However, people with blue or green eyes will experience dilation faster than people with brown eyes.
While the dilated eye exam may be over rather quickly, the dilation itself continues. During this time, a person may experience the following effects of eye dilation:
- blurred vision
- sensitivity to bright lights, such as sunlight
- difficulty focusing on nearby objects
The duration of eye dilation can vary widely. According to the American Association for Pediatric Ophthalmology and Strabismus, the average dilation lasts from 4 to 24 hours.
However, several different factors affect how long the eyes remain dilated. These include:
- Eye color: People with lighter colored eyes tend to experience the effects of eye dilation for longer than those with darker colored eyes.
- Age: Younger children tend to have a very strong focus mechanism in the eye. Therefore, they require stronger drugs to dilate the pupils. As a result, a child’s eyes may stay dilated for 24 hours or longer.
- Type of drug: The type of drug that a doctor uses to dilate the pupils will affect how long the eyes remain dilated. For example, a doctor may use weaker eye dilation drops when treating a person with nearsightedness because this helps limit side effects.
Some people feel comfortable enough to drive immediately after their eye exam.
However, doctors may recommend avoiding driving while the eyes remain dilated, especially if the person has not experienced the effects before.
Where possible, people
Eye dilation can cause several side effects.
The most immediate effect is stinging, which generally occurs when the eye dilation drops come into contact with the eyes. The stinging sensation should only be brief.
In some cases, doctors may apply numbing drops to the eye beforehand to prevent the stinging sensation.
Once the dilation drops take effect, the person may experience one or more of the following:
- blurred vision
- difficulty focusing on nearby objects
- light sensitivity
Other side effects and complications, such as angle closure, may also occur. The eye doctor can monitor for any changes, and it is important to let them know about any symptoms that develop.
Allergic reaction
In very rare cases, a person may experience an allergic reaction to the eye dilation drops, which may result in red and swollen eyes.
More severe allergic reactions could produce symptoms such as:
Cycloplegia
Eye dilation can sometimes result in a temporary condition called cycloplegia. Cycloplegia is paralysis of the eye muscle that allows a person to focus.
For most people, cycloplegia occurs only while the eye dilation drops are taking effect. In rare cases, eye dilation may cause cycloplegia to last for several days. Although this can be very concerning, the condition is temporary and will go away with time.
Managing side effects
People can take some steps to manage the effects of eye dilation.
It can be helpful to take a pair of sunglasses along to the eye appointment to wear after the eye exam. Wearing these will help protect eyes that are light-sensitive due to pupil dilation.
It can also help to avoid close work, such as reading and focusing on a computer screen. This can be difficult during eye dilation.
People whose jobs involve these tasks should arrange a few extra hours off work, where possible.
Speak with an eye doctor for more information about what to expect from pupil dilation and how to manage any side effects that may occur.
Most people can expect eye dilation to last somewhere between 4 and 24 hours. Generally, the effects last the longest in people with lighter colored eyes and in children who require stronger doses of eye dilation drops.
Eye dilation is necessary for several types of eye tests, which are important for detecting various eye conditions in their early stages.
While the effects of eye dilation drops can be uncomfortable and unpleasant, they are temporary.
People who are concerned about the effects of eye dilation should speak with their eye doctor.