Of course, it will do harm to your eyes. In my opinion, you should take off your contact lenses. Even if you wear the more permeable silicone hydrogel lenses, sleeping in contact lenses is never a good idea. It can lead to eye strain, infections and dry eye syndrome. Wearing contact lenses over a long period of time, especially if you habitually sleep in them, can also lead to decreased corneal sensation, which results in decreased tear production. It can also make your eyes feel tired and strained the next day morning. Sleeping in contact lenses can lead an increased risk of conjunctivitis, also known as pink eye. This condition can be caused by an infection. Long-term contact lens use can lead to dry eye syndrome. Wearing contacts overnight can speed up this process. Sometimes there are just some situations which may make you so tired that you don't want to take them off. In this situation, wear glasses instead for at least the next day. This will be a good advice. And also you can do other thing to avoid dry eyes.
