Have you ever dreamt of a better visual perception? Here’s another eye challenge that can help improve your skills. Find the odd one out in 20 seconds.

Why it’s done
An eye exam helps detect eye problems at their earliest stage — when they’re most treatable. Regular eye exams give your eye care professional a chance to help you correct or adapt to vision changes and provide you with tips on caring for your eyes. And an eye exam might provide clues to your overall health.

When to have an eye exam
Several factors can determine how frequently you need an eye exam, including your age, health and risk of developing eye problems. General guidelines are as follows:

Children 3 years and younger
Your child’s pediatrician will likely check your child’s eyes for healthy eye development and look for the most common childhood eye problems — lazy eye, cross-eyes or misaligned eyes. A more comprehensive eye exam between the ages of 3 and 5 will look for problems with vision and eye alignment.

School-age children and adolescents
Have your child’s vision checked before he or she enters kindergarten. Your child’s doctor can recommend how frequent eye exams should be after that.

Adults
In general, if you are healthy and you have no symptoms of vision problems, the American Academy of Ophthalmology recommends having a complete eye exam at age 40, when some vision changes and eye diseases are likely to start. Based on the results of your screening, your eye doctor can recommend how often you should have future eye exams.