In the Journals

Ray tracing method yields superior toric IOL power calculations

A ray tracing method that utilized combined keratometry and anterior and posterior topography/tomography data in conjunction with toric aspheric lenses yielded superior predictive precision, researchers found.

The study included 78 eyes of 56 patients who underwent toric IOL implantation with 2.2-mm coaxial phacoemulsification.

Data collected by the TMS5 topography (Tomey) and Lenstar optical biometer (Haag-Streit) were processed using the ray tracing package Okulix (Tedics) for residual refraction prediction after implantation of a toric IOL.

The four inputs evaluated were keratometry, anterior topography, anterior and posterior topography/tomography, and a combined group of keratometry and anterior and posterior topography/tomography.

According to the authors, the mean absolute spherical error prediction was 0.27 D. Among the four inputs evaluated, cylindrical prediction errors were 0.57 D in the keratometry group, 0.56 D in the anterior topography group, 0.56 D in the anterior and posterior topography/tomography group, and 0.50 D in the combined keratometry and anterior and posterior topography/tomography group. Statistically significant differences were noted between IOL groups (P < .05).

Disclosure: Paul-Rolf Preußner, MD, PhD, is author of the Okulix software used in this study and receives royalties from Tedics. The remaining authors have no relevant financial disclosures.

A ray tracing method that utilized combined keratometry and anterior and posterior topography/tomography data in conjunction with toric aspheric lenses yielded superior predictive precision, researchers found.

The study included 78 eyes of 56 patients who underwent toric IOL implantation with 2.2-mm coaxial phacoemulsification.

Data collected by the TMS5 topography (Tomey) and Lenstar optical biometer (Haag-Streit) were processed using the ray tracing package Okulix (Tedics) for residual refraction prediction after implantation of a toric IOL.

The four inputs evaluated were keratometry, anterior topography, anterior and posterior topography/tomography, and a combined group of keratometry and anterior and posterior topography/tomography.

According to the authors, the mean absolute spherical error prediction was 0.27 D. Among the four inputs evaluated, cylindrical prediction errors were 0.57 D in the keratometry group, 0.56 D in the anterior topography group, 0.56 D in the anterior and posterior topography/tomography group, and 0.50 D in the combined keratometry and anterior and posterior topography/tomography group. Statistically significant differences were noted between IOL groups (P < .05).

Disclosure: Paul-Rolf Preußner, MD, PhD, is author of the Okulix software used in this study and receives royalties from Tedics. The remaining authors have no relevant financial disclosures.