This invention relates to compounds of the general formula: in which the variable groups are as defined herein, and to their preparation and use. An example computing device includes a wireless communication module and a processing unit. The server-based development application has a server-based compiler. The third lens element with positive refractive power has a convex image-side surface. In another embodiment, the tapered body is solid and formed of a porous biocompatible material having sufficient structural integrity to maintain the intradiscal space and normal curvature.