It was said it can improve your vision. There is record saying that in 1930s, a teacher used Bates eye palming to treat 2180 students and almost 45% of them could get rid of glasses finally. Then eye palming is popular among people. I believe it can improve your vision if you can insist it year by year.
I don't think it can improve the vision, it is just a good way to relax your eyes. Some people do it because they just enjoy the process of relaxation. You should not rely on it to improve your vision.
Most of the poor vision is caused by excessive eye fatigue. Palming is a technique that is used to relax the eyes. Doing eye palming correctly can enough rest in a short time and your vision can be improved in flashes. If you insist on doing it, these improvements can last longer and become greater over time.