In one word: no! In more words: the conjunctival membrane makes it impossible for the lens to get lost in the back of your eye. If you can’t see the contact on your eye, check your surroundings. Rarely will the lens get stuck to the inside of your upper eyelid. If this happens, stay calm and blink to dislodge it - it doesn’t pose any harm to your eye. Contact your eyecare professional if your problem persists.