Comparison of through-focus image sharpness across five presbyopia-correcting intraocular lenses

Abstract

Purpose: To assess through-focus polychromatic image sharpness of 5 FDA-approved presbyopia-correcting intraocular lenses (IOLs) through a range of object vergences and pupil diameters using an image sharpness algorithm.

Design: Laboratory investigation.

Methods: A 1951 USAF resolution target was imaged through Crystalens AO (AO), Crystalens HD (HD), aspheric ReSTOR +4 (R4), aspheric ReSTOR +3 (R3), and Tecnis Multifocal Acrylic (TMF) IOL in a model eye and captured digitally for each combination of pupil diameter and object vergence. The sharpness of each digital image was objectively scored using a 2-dimensional gradient function.

Results: AO had the best distance image sharpness for all pupil diameters and was superior to the HD. With a 5-mm pupil, the R4 distance image sharpness was similar to the HD and at 6 mm the TMF was superior to the HD, R3, and R4. The R3 moved the near focal point farther from the patient compared to the R4, but did not improve image sharpness at intermediate distances and showed worse distance and near image sharpness. Consistent with apodization, the ReSTOR IOLs displayed better distance and poorer near image sharpness as pupil diameter increased. TMF showed consistent distance and near image sharpness across pupil diameters and the best near image sharpness for all pupil diameters.

Conclusions: Differing IOL design strategies to increase depth of field are associated with quantifiable differences in image sharpness at varying vergences and pupil sizes. Objective comparison of the imaging properties of specific presbyopia-correcting IOLs in relation to patient's pupil sizes can be useful in selecting the most appropriate IOL for each patient.