Tecnis Symfony Intraocular Lens with a “Sweet Spot” for Tolerance to Postoperative Residual Refractive Errors

Abstract

Purpose: To investigate the impact of residual astigmatism on visual acuity (VA) after the implantation of a novel extended range of vision (ERV) in-traocular lens (IOL) based on the correction of spherical and chromatic aberration. Method: The study enrolled 411 patients bilaterally implanted with the ERV IOL Tecnis Symfony. Visual acuity and subjective refraction were analyzed during the 4-to 6-month follow-up. The sample of eyes was stratified for four groups according to the magnitude of postoperative refractive astig-matism and postoperative spherical equivalent. Results: The astigmatism analysis included 386 eyes of 193 patients with both eyes of each patient within the same cylinder range. Uncorrected VAs for distance, intermediate and near were better in the group of eyes with lower level of postoperative astigmatism, but even in eyes with residual cylinders up to 0.75 D, the loss of VA lines was clinically not relevant. The orientation of astigmatism did not seem to have an impact on the tolerance to the residual cylinder. The SE evaluation included 810 eyes of 405 patients, with both eyes of each patient in the same SE range. Uncorrected VAs for distance, intermediate and near, were very similar in all SE groups. Conclusion: Residual cylinders up to 0.75 D after the implantation of the Tecnis Symfony IOL have a very mild impact on monocular and binocular VA. The Tecnis Symfony IOL shows a good tolerance to unexpected refractive surprises and thus a better "sweet spot".