Exactly when they are perfect, the eyes can commit its
shunting lines are the case of the myopes, hipermetropes and the astigmatas,
where these structures slightly take off the rays luminous of its passage. Nobody is born with these
shunting lines of refraction, but they can appear early, still in infancy, or well later, in the adult age. At the times they arrive in double dose: she has people that she presents myopia and astigmatism at the same time. In both the situations not if enxerga nor of far, nor of perto.Mas see this well are not illness. In the myopes the ocular globe is more long than the
normal one. You are enough to one mílimetro of excess to have 3 degrees of myopia. The light rays enter and form the image before arriving at the retina, where this would have to occur. All embaçado is the form that the myope enxerga what it is far. Of close it does not have problem. In hipermetropes, in contrast of that it occurs in the myopia, the ocular globe is a bit shorter of the one than the normal one. Thus, the focus of the image composes after the retina.Nos astigmatas its problem appears because the bending of the córnea is modified, with a more oval format of the one than redondo.Dessa form, the light when entering in the eye, finishes if exhausting, producing two different focos in the retina. It has difficulty to enxergar of far and close.