Abstract: The disclosure relates to knife blades for precision cutting, such as in optical surgery, wherein the blade or cutting edge is formed from a molded plastic filled with particulate material which is much harder than the plastic, the particles of particulate material being generally smaller in their largest dimension than the radius of curvature of the apex of the cutting edge. A thin coating of a metal which is much harder than the filled plastic is coated onto the cutting edge to replicate the molded shape and provide substantial additional hardness to the blade edge. In a further embodiment, a transducer is molded into the blade body adjacent the edge with all processing steps being at temperatures below those harmful to the transducer. Another embodiment provides light conducting elements molded into the blade body for measurement of cut depth or the like.