How to know if the lens is still in the eye or it fell? i am not sure if it is still inside?

If you are talking about a contact lens, it can slip off of the front of the eye- which is the cornea. It can slip off to the white of the eye either under the upper or lower eyelid. You may need help looking. If you look up and pull the lower lid down you may see it. Or look down and look underneath the upper eyelid. Get help at your eye doctor if needed.

Are you wondering about your contact lens being still in? If you're not sure about your contact lens being on your eye, you should have an evaluation by your eye care provider. Well fitted contact lenses don't fall out easily and you should be able to tell, based on your vision, if the contact is still in or not. Having multiple contact lenses on your eye could be a big problem.