Alterations in elastin of the optic nerve head in human and experimental glaucoma.

The optic nerve heads from normal and glaucomatous eyes of humans and monkeys were examined by light and electron microscopy for the presence and distribution of elastin. Elastin densely lined the insertion of the lamina cribrosa into the sclera and was prominent in the laminar beams. The long axis of elastin paralleled that of the collagen fibrils and corresponded to the directions of expected forces on the tissue. In glaucomatous eyes elastin molecules were curled instead of straight and seemed disconnected from the other elements of the connective tissue matrix. Laminar beams stretch and reorganise their substructure during glaucomatous atrophy, probably leading to changed compliance. Differences in elastin function may have a part in susceptibility to glaucomatous injury.