I don't wear glasses but when my eyesight is going I will try the exercises prescribed by Harry Benjamin in his book Better Sight Without Glasses. First published 1929 it is a complete self-treatment system for defective vision.
I bought the book because I loved the illustrations. Especially the one where the woman has to swing from side to side. "The gentle swaying, or swinging, has the effect of relaxing the whole nervous system, and should be practiced two or three times a day for five to ten minutes each time, or whenever the eyes feel tired and aching." No wonder the woman in the last illustration looks like she is going to be sick.