power 4dA convex lens of power 4D is kept in contact with a concave lens of power 3D, the effective power of combination will be . View Solution; The power of a concave lens is 10 D and that of aGracias a la tecnología 4D, el Superconcentrado 4D Powerlift actúa directamente sobre los componentes de la matriz extracelular: colágeno, elastina y ácido hialurónico, sustancias