Treatment of advance keratoconus using donor bowman layer: the zaman technique of bowman layer transplantation (Type I & Type II)

surface and anterior segments. These include tear ilm dynamics, anterior and posterior higher-order aberrations (HOAs), and corneal light scattering Considering the results of previous studies, which analyzed the amount of scattering produced by different lamellar keratoplasties, the bowman layer transplantation into the mid corneal stroma, may increase, as expected, some corneal backscattering After bowman layer transplantation the lattening effect of BL directly affects the spherical aberration.