Influence on intraocular lens power calculation of corneal radii measurement using an image-guided system

Abstract

To analyze the influence on intraocular lens (IOL) power calculation of corneal radii measured by the Verion Image-Guided System in comparison with those measured by partial coherence interferometry (PCI) (IOLMaster) and optical low-coherence reflectometry (OLCR) (Lenstar) systems. International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. Prospective case series. One eye of ophthalmologically healthy volunteers was examined with the image-guided, PCI, and OLCR systems. Corneal radii could be measured with all 3 devices; axial length (AL) and anterior chamber depth (ACD) could be measured with PCI and OLCR only. The IOL power calculations for the Acrysof SN60WF IOL using 4 formulas were compared between the image-guided system and both the PCI device and OLCR device. For IOL calculation with the image-guided system, the AL and ACD of the device used for comparison were applied. Of the 150 volunteers, 136 (mean age 39.60years±17.31 [SD]) had valid measurements with all 3 devices and were included in the analysis. Compared with PCI, the image-guided system measured statistically significant larger values for corneal radii and IOL power calculations for all 4formulas. There were no statistically significant differences between the image-guided system and the OLCR device. In both groups, the surgeon would have chosen the same IOL power in approximately 60% to 65% of cases and a ±0.5 diopter different IOL power in approximately 30% to 35% of cases when using the image-guided system. The IOL power calculation using the image-guided system showed statistically significant differences compared with the PCI device but not when compared with the OLCR device. The clinical relevance of this theoretical approach remains to be evaluated. Drs. Auffarth and Holzer received travel grants and lecture fees from Alcon Pharma GmbH and Carl Zeiss Meditec AG.