The evolution of the diseases which affect the collagen structures of the eye must be oriented in accordance with the study of the membranes richest in connective tissue—that is, the cornea, which contains more than 90%; the sclera and the iris; the ciliary body; the choroid; the retina, and the optic nerve, which are rich in connective tissue. The vitreous is not included, since it consists of a material similar to collagen.
The diseases of these various membranes are worth studying in connection with generalized diseases, since careful observation of the ocular status in these diseases permits one to see exactly what occurs in other regions of the connective tissue, less accessible to direct examination.
In a large percentage of cases the ocular involvement appears before the general disease becomes evident; hence the discovery of pathological lesions in the collagen structures of the eye, especially when a specific etiologic factor
CONTARDO R. Evolution of the Collagen Diseases. AMA Arch Ophthalmol. 1956;56(4):568-576. doi:10.1001/archopht.1956.00930040576006