An alignment feature formed in a lens block during manufacturing has a precise spatial relationship to an optical surface of the lens block such that precise alignment of the alignment feature within the lens block ensures precise alignment of the optical surface within the lens block. Precise alignment of the alignment feature within the lens block is readily assessable whereas precise alignment of the optical surface within the lens block is not. A determination is made as to whether the optical surface is aligned within the lens block by determining whether the alignment feature is aligned within the lens block, and if not, the extent of any misalignment. The extent of misalignment may then be used to adjust the manufacturing process to eliminate the alignment error.