It's actually making use of the pinhole effect. Not so much about concentrating light to create a focus. The clear vision is manifested by reduction of the circle of blur vision that a myopic eye experiences. The higher the myopia, the greater this circle of blur vision is on the retina.
I know it's kinda technical but ya, like what Himeko said, this effect may or may NOT be long-termed. Current studies are not enough to support the claim that hey, this works effectively permanently!~ |