An optical method for determining collagen bundle orientation in bovine pericardium includes the use of a system having a light source which transmits light through a first polarizer, a tissue for making a prosthetic valve leaflet, and a second polarizer, where the light then illuminates a detector plate. The light that illuminates the detector plate is used to determine the orientation of collagen fiber bundles. The orientation of the collagen fiber bundles is used to determine where to cut the leaflet edges.
