Impact Of Pupil Size And Corneal Spherical Aberrations On The Performance Of Monofocal Intraocular Lenses: An Experimental Model.

To evaluate three different monofocal intraocular lenses (IOLs) in various optical conditions using a comprehensive in vitro model.

Rothschild Foundation Hospital, Paris, France

In vitro wavefront acquisition was conducted using a wavefront sensor on three monofocal IOLs from the same manufacturer (Zeiss):  a spherical lens (Spheris 209M) and two aspherical lenses—an aberration-neutral lens (Asphina 409M) and an aberration-correcting lens (Asphina 509M). Through-focus Modulation Transfer Function (MTF) curves (average MTF between 0 and 50 lp/mm) were calculated for synthetic numerical modified ISO-2 eye models with 8 different apertures (2-5.5mm, every 0.5mm) and 21 different corneal spherical aberrations (SA) (-0.49 to 0.91µm at 5.15mm diameter in IOL plane, in increments of 0.07µm), resulting in a total of 168 distinct eye models.

Corneal SA showed no significant impact on optical performance for small apertures (up to 2.5mm). However, for larger apertures (ranging from 3mm to 5.5mm), we observed notable variations in the maximum MTF value, Depth of Focus (DOF), Refractive Error Tolerance (RET), and IOL Effective Power Shift (EPS). These variations depended on the IOL models with the best contrast, minimal RET and EPS changes, and reduced DOF occuring when the IOL SA compensated for the corneal SA.

We introduce a comprehensive in vitro model that confirms the substantial influence of postoperative pupil size and corneal SA on the performance of IOLs after implantation. This model facilitates the quantification and comparison of various IOL designs.