The Israeli app GlassesOff has been tested successfully on 32 Israeli Air Force pilots. On average, a 35% improvement in visual acuity (sharpness and clarity) was achieved after 3 months of exercises for just 12-15 minutes, three times a week. GlassesOff improves the brain, not the eyes.
http://www.timesofisrael.com/israeli-eye-exercise-app-lets-iaf-pilots-dump-glasses/