Half of all contact lens wearers in the U.S. have reported sleeping with their contacts in. (Source)
That’s a bad idea, in most cases.
New innovations in contact lens materials and the growing popularity of daily and two week disposable lenses have reduced the amount of lens-related infections. However, unlike prescription glasses, contact lenses require you to adhere to specific care instructions to avoid harming your eyes.
There are many contact lenses designed for extended wear (continual wear for up to 7 days) but considering only 5% of all contact lens wearers in the U.S. are prescribed extended wear lenses, it can be assumed that most people are risking their eye health by sleeping with their contacts.
The reason few people are prescribed extended wear lenses is because eye doctors are aware of the higher risk of infections and corneal injury. Wearing daily disposable soft contacts, where a fresh lens is used each day, virtually eliminates the chances of protein build-up and the reuse of non-sterile saline solution.
The vast majority of contact lens related complications are self-inflicted, brought on by overwearing. If you consistently sleep in your contacts, and they aren’t intended for that use, consider the following: