avalon posted a topic in General Optical DiscussionIt‘s widelly believed that astigmatism is hereditary disease but why it is so widespread then? Evolutionary it would disadvantagious to have poor eyesight which is crucially important for detecting predators and survival. There is new explanation for astigmatism which makes more sense. It's being caused by eyelid pressure and explains why astigmatism is so prevalent among readers. When you read you often are looking down and there is greater pressure in bottom area of cornea. So if eyelids can alter cornea shape it should be possible same way pemanently correct sight? Only device I‘m aware capable of reshaping temporarelly cornea is Ortho K lens. But these lens seems to be ridiculously expensive just for thin plastic lens and being sold only in richer countries. It would be great if there was analogical device for poor population to fix eyesight using orthokeratology.