Microstructural Alterations in the Human Sclera: Do Age and Race Matter?

Glaucoma, an ocular disease resulting from a loss of retinal ganglion cell function, is the second leading cause of blindness in the world, according to the World Health Organization. Approximately 120,000 are blind from glaucoma, accounting for 9% to 12% of all cases of blindness in the U.S. Earlier studies have suggested that mechanical forces play a critical role in the progression of glaucoma [1–3]. Sigal, Flanagan, et al. studied the influence of varied factors including geometric features and material properties using both generic and individual-specified optic nerve head (ONH) models developed in their work, and they demonstrated that scleral mechanical properties had by far the largest influence in the ONH biomechanical environment (ONH strain) [4–8]. Downs, Burgoyne, et al. defined the effects of the scleral shell and collagen fiber orientation through the examination of displacement [9]. The above studies show that the ONH mechanical properties depend strongly on the microstructure in the scleral shell.