Evaluation of the Impact of Intraocular Lens Tecnis Z9000 Misalignment on the Visual Quality Using the Optical Eye Modeling

Purpose: The aim of this study was to investigate the effect of misalignment (tilt & decentration) of IOLs in cataract surgery using Liu-Brennan optical eye model in a simulation. Methods: A phantom with the real eye parameters –Liu-Brennan model– and Tecnis Z9000 IOL were used for simulation. Results: Results showed that with 0.4 mm decentration and more the modulation transfer function (MTF) and contrast were reduced continuously in the ±X Axes. IOL decentration in ±Y axes showed a symmetrical reduction of MTF and contrast with increasing the decentration. In the ±X and ±Y axes, 1º to 8º IOL tilts had no significant effect on the MTF and contrast of the eye. Conclusion: It can be said that the decentration of Tecnis Z9000 IOL in the ±X and ±Y axes will reduce the optical quality of the person, specially for decentration more than 0.4 mm this effect is very significant. Therefore using the compensation methods for improvement of the optical quality is essential. But up to 8º IOL tilt in vertical and horizontal axes had no significant effect on the visual quality of the patient.