A method and mold assembly to control the polymerization of a cast optical device. The backplane includes a bottom surface and a side wall. The valve leaflet includes a commissure that can reversibly seal for unidirectional flow of a liquid through the valve, and a biodegradable adhesive between the valve leaflet and the valve frame to hold at least the commissure of the valve leaflet in a static relationship relative the valve frame for a predetermined time once implanted in vivo. After wafer thinning and backside metal deposition, the wafer is exposed to heat to thermally decompose the sacrificial polymer into gases.