Theoretical, computer-assisted prediction versus SRK prediction of postoperative refraction after intraocular lens implantation

Abstract

The postoperative refraction prediction was evaluated in 99 patients with a 19.0-diopter standard power anterior chamber lens using a theoretical, computer-assisted method based on Gaussian optics and an empirical intraocular lens calculation method based on the SRK formula. Both the theoretical and the empirical predictions accorded with the observed values in the near emmetropia region. In the prediction of ametropia, the SRK method showed a tendency to predict refractions that were lower the actual values in hyperopic eyes and higher than the actual values in myopic eyes. The bias of the SRK method may be due to the use of an erroneous refraction factor that converts the ametropia to the diviation in implant power from the emmetropia power. By introducing an individual refraction factor, the accuracy of the SRK method approached that of the theoretical method.