If the eye strains sufficiently, the muscles undergo spasm, which then changes the actual shape of the eye. With frequent strain, the eye remains in a shape that impairs distant vision. The malady progresses. Once thrown out of shape, the cornea causes poor drainage of the internal eye fluids, which in turn increases the eye pressure and eventually elongates the posterior position of the eye. The result is further nearsightedness.
Corrective lenses tend to increase myopia, especially for computer users.
Because they bend the incoming light patterns, lenses reduce the visual field by at least six percent, and distort color waves by an even greater amount. Our technologically advanced society promotes a characteristically more nearsighted population. Even though the causes of myopia are partially genetic, the main reason for widespread myopia is the modern need to view things close-up and to fix things through symbols and simulations. The eyestrain at the interface begins with the modern ideal of vision. From Descartes to Berkeley, the modern understanding of vision inculcates the fixed stare, as David Levin has shown in his study of modern vision.