The computer calculation of intraocular lens power. A clinical study.

A series of forty eyes received intraocular lenses (IOLs) of power +17, +19, or +21 D after consideration of computer calculation based upon data of corneal curvature, axial length, and anterior chamber depth using the formula of R. D. Binkhorst. Results were compared with those of a control group of ninety eyes which were given IOLs of standard +19 D power. No difference was found between the resulting visual acuities or range of postoperative refractions. The preoperative refraction was found to offer no guide to the selection of IOL power. The results were analysed in detail and it was found that the computer prediction of postoperative refraction for the IOLs implanted was of a high level of accuracy. This suggests that improved clinical results are to be expected from a close adherence to the IOL power calculated by a system which has been tested for accuracy and reliability. The cautious minor adjustment of IOL power as in the protocol of this study does not influence the outcome.