Falling asleep with contact lenses is not a safe practice and, in the long run, could cause eye damage . Sleeping with these devices occasionally, for a nap a couple of hours at the most, does not cause any problems.
After a night with contact lenses, however, you may have blurred vision and irritated eyes when you wake up. Furthermore, not removing contact lenses for several hours also increases the risk of infections such as keratitis, a very annoying inflammation of the cornea.
