1. A set of contact lenses, each lens in the set comprising: a differentiable posterior surface including a posterior optical zone (POZ) having a POZ diameter and a normal to a surface of the POZ passing through a center of the POZ; at least five peripheral zones (PZs) each of which encircles said POZ and has corresponding inner and outer perimeters, wherein immediately adjacent peripheral PZs from said at least five annular PZs share a perimeter, the at least five PZs having respectively corresponding optical power parameters that define slopes of the posterior surface with respect to the normal; and a POZ optical power of the lens corresponding to the POZ and common among the lenses in the set.