Keratoconus is the pathological deformation of the cornea that has non-inflammatory nature. Under the influence of structural changes, the cornea is getting thinner and gains a cone shape instead of spherical, as it is supposed to have naturally. The disease occurs because the main substance of the cornea loses its natural mechanic abilities. Its structural fibers lose their strength. The pressure inside the eyes makes the cornea protrude. Usually the disease develops on both eyes.