Synchrotron X-ray diffraction study of corneal stroma

Using a synchrotron X-ray source, it has been possible to record a low-angle diffraction pattern from fresh bovine corneal stroma.The pattern can be interpreted as arising from the short-range order packing of collagen fibrils in lamellae. Model calculations suggest that the positions of the fibrils remain correlated over distances corresponding to, at most, three fibril diameters (~ 120 nm). These results support theories of transparency of the cornea based on short-range order.Further, a study of the fibril spacing as a function of hydration confirms that water uptake occurs largely between the lamellae and in regions devoid of collagen fibrils, and shows that the fibril diameter increases with hydration.