Long interested in investigating the seemingly far-fetched claims people have made that vision could be improved naturally, without glasses, I attended Leo Angart's course, in which he puts the principles in this book into action. To my amazement, by doing the exercises over the several days of the course, my wife and I both found we needed, on average, between our four eyes, about 3/4 of a diopter less prescription correction per eye.
Both of us, who had been requiring increased prescriptions every couple of years, were now able to return to the prescriptions of several years before (about a diopter less per eye) and spend more time wearing no glasses at all within a few days. As important, we learned that some of the factors that make it hard for many of us to see clearly, also put long-term pressure on the eyes, setting them up for more serious problems in old age. Thus, some of the exercises Leo describes here not only improve sight, but also appear to protect our eyes over the course of our lives.