Characterization of collagen from normal human sclera.

Human scleral tissue contains approximately 50% collagen by weight, consisting predominantly of type I collagen. There is little or no evidence for the presence of substantial quantities of type II, type III or other collagen types. There appears to be no difference in either collagen content or genetic type in sclera between adult and juvenile tissues or between anterior and posterior segments of the sclera, although, with increased age there is a marked increase both in the extent of glycosylation of the collagen and its resistance to solubilization by treatment with pepsin.