Many authors, and particularly de Wecker, have believed that the efficacy of sclerotomy in cases of increased tension consisted in the development of a peculiar permeable scar—a filtration scar. . . . The scar is broadest in the outer layers of the sclera, then becomes narrower in the middle layers, and again becomes broader in the most internal portion of the sclera. . . . The choroidal scar is much more extensive than the scleral scar. . . . With the choroidal scar is intimately connected that of the retina.