Since they have came out with certain versions of extended wear contact lenses there are a growing number of people who have started sleeping in their contact lenses. Some of the newer contact lenses in this market say you can wear them up to 30 days in a row, and sleeping in them is okay.
There are some people who follow these rules, and others who would rather play it safe than sorry. Most of the time the types of contacts that allow you to do this will be prescription and not costume or theatrical types of contact lenses.
If you are buying green contacts that are prescription and the manufacturer says they are extended wear then you should be able to sleep in them, but overall it’s not recommended to start as a habit. If you are tired, or don’t have the solution readily available then one or two nights won’t typically hurt. There is really no reason to sleep in them longer than that because you are just increasing your chances of injury or other problems.
If you buy plano contact lenses solely for costume or Halloween purposes, these will not usually be extended wear so they should most likely not be slept in unless you get explicity okay from your eye care specialist.
There was a study done at a University that tested the effects on sleeping in your contacts and if they caused any damage to your eyes. They ultimately decided that sleeping in your contact lenses increased your long-term risk of developing keratitis which is inflammation of your cornea.
The softer contact lenses were more five times more damaging to the person wearing them compared to the extended wear contact lenses. So if you do decide to sleep in them, make sure they are designed to be slept in, and we still don’t recommend making a habit of it.