Cornea

This is a cross section of the cornea, with the anterior chamber on the left. In the front is a layer of stratified corneal epithelium. Right beneath this layer is a thin layer of Bowman's membrane. The stroma of the cornea is avascular and is rich in collagen fibrils and some fibroblasts. On the posterior end is the endothelium of the cornea. How does the cornea remain transparent despite its high concentration of collagen fibers?