The development of the angle of the anterior chamber in vertebrate eyes.

The development of the angle of the anterior chamber of the eye in chick embryos (avian eye), in new born rats (rodents), in calf fetuses (ungulates) and in humans (primates) has been studied. The main determinant in the configuration of the angle is the two-layered structure of the mesoderm of the ciliary body: the external muscular layer inserted into the spur and growing with same growth rate as that of the corneoscleral mesoderm and internal fibrovascular layer giving rise to the ciliary processes and growing with same growth rate as that of the neural ciliary and iris epithelium. First the neural epithelium grows faster than the corneoscleral mesoderm and the ciliary processes appear anteriorly positioned and later the corneoscleral mesoderm grows faster than the neuroepithelium and the ciliary processes appear posteriorly positioned. The eyes of premature and low birth weight babies present the different stages of normal embryological development of the angel. The angle in eyes of various embryopathies and developmental diseases presents aspects similar to those of the premature and low birth weight babies. The etiopathogenic mechanism in cause is the same in both groups: arrest of development. During the first post-natal years, the corneoscleral mesoderm grows at a greater rate than the inner neuro-epithelium and the region of the most active growth is located at the ora serrata. That is why, during this period, the ora serrata recedes, giving rise to the formation of retinal teeth, the angle despens and makes a recess and the Lange fold disappears.