I have been using for a couple of months. I do not remember exactly but I think surely more than 4 months. Before AmblyoPlay, my left eye could not see much, especially the right part of the image, it was kind of greyed out. However, now I can even see more of the right sight of the picture. It’s less grey and I can see more. I would definitely recommend AmblyoPlay to others. I wish I had it when I was a child.