Abstract: The power of an intraocular lens is verified under sterile operating room conditions prior to its insertion into a patient's eye. A testing apparatus amenable to single hand operation is utilized which is comprised of two slidably interengaged plates having two series of lenses adapted to be aligned upon optical axes perpendicular to the plates. The aligned lenses constitute adjustable minus power reference lenses. An intraocular lens to be tested is placed atop an appropriate minus power reference lens, and the surgeon views a stationary object through said lens system while moving the apparatus. By observing whether the stationary object appears to move in a direction with or against the lens movement following minor adjustments in the power of the reference lens, the power of the intraocular lens can be determined.