What is the cause of such visual impairments as myopia and hyperopia?

What is the cause of such visual impairments as myopia and hyperopia? What processes are corrected with the lenses of glasses? Tell us about the prefilakieka of these diseases

The cause of these diseases is the thickening or narrowing of the lens of the eye. It is essentially a natural lens. If it is deformed, then the focal length changes and the person sees either close objects or distant ones. The lenses of the glasses allow you to change this focal length and the person begins to see normally. For the prevention of these diseases, it is necessary to take breaks while working at the computer, use eye drops and consume vitamins, since it is because of their lack that the lens can be deformed.