I have perfect vision, no pain, no watery, how do i know if i have lazy eye?

Lazy eye: A simple eye exam can give you the answer.

Simple test: This should be easy. Cover one eye & look at an eye chart or similar set of figures. Is the vision perfect ? Do the same covering the other eye. If both eyes see perfectly you don't have a "lazy" eye. The term is a lay term for amblyopia, which is where the brain decides to "turn off the camera" input from a weak eye or one that caused double vision. Once off it stays off or very poor.