I also see the benefit in improving my eyesight. http://pinhole-glasses.com/ I tried the ghetto version of pinhole glasses and put tape onto a cheap pair of sunglasses. The simple verson of why I think that it works is the glasses are like squinting for you. Also it reminds me of a eye exercise that I do (https://en.wikipedia.org/wiki/Bates_method) We both have seen a video camera struggling to focous on an image though a wndow, I think that our eyes are sometimes like the video camera...so I call my eye excercises "stretching my eyes" because sometimes they are lazy and only want to look at stuff near by. If you are a readerthen you might want to get the book
Vision for Life: Ten Steps to Natural Eyesight Improvement Paperback – October 2, 2012

by Meir Schneider Ph.D. (Author) (In the mean time watch this video