An intraocular lens, and a system and method of customizing at least one characteristic for an intraocular lens, in accordance with a regression that indicates the postoperative spherical aberration at the iris plane of a patient aphakic eye, in order to obtain a desired postoperative condition. The lens, system and method of customizing at least one characteristic of an intraocular lens may include measuring at least one biometric parameter of an eye at a desired light level, determining a desired postoperative condition of the eye, obtaining a corneal spherical aberration and an anterior chamber depth of the eye, and empirically calculating a spherical aberration at an iris or pupil plane of the eye, based on a regression formula comprising at least the corneal spherical aberration and the anterior chamber depth, and cross products thereof.