It's something that happens to most every contact lens wearer from time to time: a lens gets caught "behind your eye." This experience can be stressful and uncomfortable, but if you know how to deal with it properly, you can minimize the stress and discomfort.
What you need to realize
The contact is not really behind your eye. The eye anatomy simply does not allow for it -- there is no area behind your eye for the contact to travel to. When the contact seems like it is stuck behind your eye, it's really just far under either your upper or lower eyelid. Remembering this will help prevent you from panicking when your lens gets lost.
How to retrieve the contact
First, close your eyes and ask yourself if you can feel a pressure sensation or slight discomfort in any area around your eye. This might be along your upper eyelid, towards one corner, or along the bottom of your eyelid. The area where you feel this sensation is where the contact likely is. Open your eyes and put an eye drop in the eye with the lost lens. Then, close your eye again and use your fingers to slowly massage the area where you felt the pressure sensation. Move your fingers from the outer edge of the eye towards the center.
After massaging your eye for a minute or two, open the eye and look in the mirror. You may see the folded up contact peeking out from under one of your eyelids. If so, use your (clean) finger to slide the contact further towards the center of your eye, and then "pinch" it out of your eye as you normally would when removing a contact. If you don't see the lens yet, close your eye, and massage for another minute or two before checking again.
If you don't feel any pressure on one edge of your eye, then start by massaging one lid. Check in the mirror to see if the contact appears. Then, massage another area of the eyelid. Check again. Keep repeating this process, and eventually you should massage the right area and dislodge the contact.
If you can't retrieve the contact
If after 10 or 15 minutes of massaging and checking you don't see any signs of the contact lens, then it's time to visit your eye doctor. He or she can use an imaging device to locate the contact and then gently slide it out of your eye. This should not be painful, and it will only take a few minutes. Contact a professional like Jeffrey C. Fogt, OD for more information.