On the impact of multifocal IOL decentration and tilt on retinal image quality

Purpose The design of advanced (such as multifocal) intraocular lenses (IOLs) is based on the exact alignment of the optical element with the center of the pupil and its optical axis with the line of sight of the eye. It is the purpose of this study to evaluate the impact of multifocal IOL decentration and tilt on retinal image quality. Methods A series of patients implanted with multifocal IOLs were evaluated with a Scheimpflug imaging device (GALILEI Dual Scheimpflug Analyzer, Ziemer Switzerland), that was utilised to evaluate centration and tilt of the IOLs. Wavefront aberration was recorded using a retinal ray tracing device (iTrace, Tracey Technologies Houston, USA). Induced high order aberrations were correlated to the orientation of tilt and the location of the IOL. Results In multifocal IOLs, decentration in recpect to the pupil center is more detrimental to retinal image quality than tilt. Moreover, multifocal IOLs are more sensitive to tilt and decentration than monofocal IOLs in respect to the induced aberrations. Conclusion Modern imaging technologies in combination with wavefront abberation measurements may elucidate the impact of IOL location in the eye in retinal image quality. In certain cases, such as in diffractive lenses, where wavefront sensing has inherent limitations, retinal image quality may be evaluated by appropriate computer modeling.