In a conventional lens design, spherical aberrations occur because the dioptric power in the periphery of the lens is different from the dioptric power in the center of the lens (optical axis). These aberrations influence contrast sensitivity and depth of focus. Increasing the depth of focus means decreasing the contrast sensitivity and vice versa.
An aspherical optic has been altered to reduce spherical aberrations; the dioptric power in the periphery and center of the lens are equal. Quadrimax IOLs are aberration-neutral. The natural aberrations of the cornea are respected, delivering both an optimal depth of focus and good contrast sensitivity.