CLs are small lenses that are placed on the cornea, which is the front surface of the eye. They usually have a prescription so they allow you to see clearly without wearing glasses. The most common types are soft and flexible, and when they are inserted they are usually comfortable. Some CLs need to be replaced every day and some every month. CLs should be taken out before sleeping, and they should be removed before showering or making any contact with water.

CLs correct your vision without needing to wear glasses. As they sit directly on and fully cover the front surface of your eye, it gives you a wider field of view compared to glasses (with glasses, the lens stops where the edge of the frame is). Some people prefer how they look without wearing glasses so CLs are a great solution for them. People who play sports where glasses could get damaged may also benefit from wearing CLs. With people who have higher prescriptions or unequal prescriptions in both eyes, CLs can produce a better quality image than glasses (less minification/ magnification / reducing aniseikonia).