How to tell if I still have my contact lens still in my eye?

So I am not that blind, however I use contacts when I go out to avoid squinting (my prescription is -0.50 for both eyes). Last night I went out to the bar and put them in, however, when I got back home I only took one out of my left eye, and couldn't find the one for my right eye.

Two thoughts:
1) I may have not put it in my eye the whole night - it wasn't in the case, it may have just fallen out when I went to put it in but never noticed
or
2) It is still in my eye I just can't seem to find it

So what is the best way to tell if I still have a contact lens in my eye?

This has happened to me. If you went to take it out and it wasn't there check on the upper and lower part underneath your eyelid. Or you just lost it and didn't realize:)

If its still in your eye its going to irritate it, especially if its been in all night. However you can check by gettign a bright light and a mirror and lifting both eyelids and looking under them. The common place for a lens to get stuck is to the upper eyelid and quite far back. That can be hard to spot. It can also be quite far back on the eyeball under the top lid. If you can't spot one, get someone else to double check under a really good light. If neither of you can spot it its notlikely to be there, but if your eye feels irritated go to the optician.