you can buy day&night lenses if you dont like to clean them everyday. i slept with my lenses once or twice, actually nothing happens. try not to do it..

Hello, Of course it is not recommendable. Why need to sleep with them in the first place ?;)

Is it safe to sleep in your contact lenses? The answer generally is no – not unless you are wearing lenses specifically approved for overnight wear and are wearing them to the schedule prescribed by your eye-doctor. The fact that you might get away with an occasional nap in your lenses by no means guarantees you will be able to sleep routinely in your lenses without consequences. The fundamental problem is that contact lenses restrict the flow of oxygen to the surface of your eye (the cornea), and the longer you wear the lenses, the longer the flow of oxygen is restricted. In extreme cases of over-wearing lenses, new veins grow out into the cornea as the body attempts to correct for the oxygen deficit. So if you want to sleep in your lenses, you should start by telling your eye-doctor, and asking her to prescribe a suitable lens. So what lenses are approved for overnight wear? Many of the new silicone hydrogels are approved, including the Focus Night & Day, which is the only lens approved for a full 30-days of wear. There are also numerous conventional (hema) soft lenses that are approved for up to 7 days of extended wear – all of the major manufacturers offer such lenses. Check with your doctor, perhaps you are already wearing such a lens.

http://www.aclens.com/sleeping-in-lenses.asp