I don't wear contacts, but I've heard of a type of contact that you can safely sleep in... somehow they don't cause irritation.
This idea is for a contact lens you can't see through, it blocks out all light, to be used when napping at work or at home. I see it working one of two ways.
opaque, so nobody sees your eyes and you don't see anybody.
2) The opposite of regular opaque contacts. Everyone can see your eyes, but you can't see out (I'm not sure if that could work, it's just a suggestion).