New algorithm for calculating IOL power in post-RK eyes shows good results

This large case series found that an algorithm for calculating IOL power in postradial keratometry (RK) eyes based on data from the Pentacam rotating Scheimpflug camera system produced equivalent results to a current standard.

The authors obtained relevant IOL calculations and postoperative refractive data from 83 eyes of 57 patients treated at a private practice in Arizona with RK but no additional keratorefractive procedures or subsequent cataract surgery. They used various Scheimpflug measurements from a range of zone diameters to calculate IOL power using an Aramberri double-K-modified Holladay 1 formula. Results were compared with actual postsurgical data and IOL calculations based on the mean of the 1.0 mm to 4.0 mm rings from a current standard, the Zeiss Atlas topography system.

After adjusting for central corneal thickness, the mean pupil-centered sagittal front power over the central 4.0 mm zone provided the best results. The results were similar to those obtained using the topography system. Forty-two percent of eyes were within 0.50 D of the target, and 76 percent were within 1.0 D.