Tilt and decentration of spherical and aspheric intraocular lenses: effect on higher-order aberrations.

PURPOSE: To determine the impact of spherical and aspheric foldable intraocular lens (IOL) tilt and decentration on optical quality after cataract surgery in an intraindividual comparative study.

SETTING

Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany.

METHODS

Randomized implantation of a spherical IOL (Sensar AR40e) was performed in 1 eye and of an aspheric IOL with negative spherical aberration (Tecnis Z9000) in the contralateral eye. Three to 4 months postoperatively, the wavefront was measured and higher-order aberrations (HOAs) were calculated for virtual pupil diameters of 3.5 mm and 6.0 mm. Tilt and decentration of the IOLs were measured using Scheimpflug photography. The tilt and decentration, HOAs, and best corrected visual Strehl ratio of the optical transfer function (BCVSOTF) calculated from the wavefront aberration were compared. The effect of tilt and decentration on HOAs and optical quality was assessed using multiple regression analysis.

RESULTS

The mean optic tilt was 2.89 degrees +/- 1.46 (SD) for the spherical IOL and 2.85 +/- 1.36 degrees for the aspheric IOL. The mean optic decentration was 0.19 +/- 0.12 mm and 0.27 +/- 0.16 mm, respectively. No significant intergroup differences in IOL tilt or decentration were found. Tilt and decentration did not significantly affect the BCVSOTF with either IOL.

CONCLUSIONS

The amounts of tilt and decentration of both IOLs were not large enough to cause deterioration of optical quality. Thus, when IOL tilt and decentration are within normal limits, they do not compromise the correction of spherical aberration by the aspheric IOL.