In many cases the cornea become cloudy and the vision deteriorate as a result of a deficit of the corneal pumping machine, which is situated on the back of the cornea. In such a case, replacing the back part of cornea would mostly clear the cornea, without the need to replace the whole cornea, which mean, a lot less risky procedure and less chance of corneal graft rejection, and finally there is no need for an extensive suturing, which need to be taking out during the following years. Also we need to remember that replacing only the posterior part of the cornea would keep the tensile strength of the cornea, which is diminished in the full thickness corneal graft.