What is the difference between a lazy eye and a regular eye?

Two forms of lazy: Amblyopia means the eye cannot see well despite the appropriate prescription being worn (usually 20/40 or worse). The eye can be well aligned but the brain does not use its information. It can be caused by something blocking vision (cataract) or the eye not being aligned. Strabismus means the eye is not aligned, and will lead to amblyopia if not treated.

Non-working = lazy: Lazy eye refers to several issues that can cause the brain to quit accepting input from an affected eye, so it is not working =lazy. Example: 1 eye presents a sharp image to the brain, 1 a fuzzy image or one from a different direction. The brain chooses to keep the best image & quit "looking" at the other image. If the brain has turned off the lazy input for too long, it may be lost forever.