E valuation for the Differences of Predictive Refraction Among Three Types of Intraocular Lenses with Manufactu red A constant and Revised A constant

ABSTRACT

To compare the difference of predictive refraction among three types of PC-IOLs, we reviewed retrospectively 180 cataractous eyes that had undergone phacoemulsification and PC-IOL implantation by the same surgeon at 2 months postoperatively. The inclusion criteria consisted of the axial length ranging from 22 mmto 24.5 mm, the best corrected visual acuity better than 0.9 in Snellen chart and the astigmatism within+/-1 diopter at the time of postoperative 2 months. Patients were divided into 3 groups according to PCIOL types. Group 1 comprised of AMO(r) PhacoFlex SI30NB(71 eyes), group 2 of Acylsof(r) MA60BM(58 eyes), and group 3 of CILCO(r) PMMA single-piece MZ60BD(50 eyes).IOL power calculations were processed by SRKII with manufactured A constant and with revised A constant. There were no significant differences in predictive error within+/-1 diopter among different groups(P>0.05).With manufactured A constant, SI30NB with polypropylen haptics showed hyperopic shift in relative error. MZ60BD with a single-piece and narrowing haptic angle showed more myopic shift than MA60BM(P<0.05). But with revised A constant, there were no significant differences in myopic or hyperopic shift and showed more enhancement in the accuracy of predictive refraction than with manufactured A constant.