Can glasses fix a lazy eye? how?

Sometimes: Depends on the cause, vision, and amount of eye deviation. Sometimes glasses can be made to get the eyes to look straight ahead.

Depends on the cause: If the lazy eye is turned one direction due to a prescription issue, glasses can straighten it. Prism placed in the glasses lenses can treat more resistant forms. Surgical alignment of the eye at a young age is a more permanent treatment. If the lazy eye is aligned but not able to see well, patching the other at a young age may help improve the vision.