To compare the posterior capsule opacification ( PCO ) inhibiting effect of the round anterior and sharp posterior optic edge profile of the Clariflex silicone intraocular lens ( IOL ) [ AMO Inc , Santa Ana , California , USA ] with that of the double-round edge profile of the SI40 ( Phacoflex ; AMO Inc , Santa Ana , California , USA ) silicone IOL over a period of three years .
