Freeform EDOF IOL design for eyes that have undergone LASEK

The design of intraocular lenses (IOLs) is currently based on a standardized eye model. However, refractive surgery techniques such as laser-assisted subepithelial keratectomy (LASEK) correct ametropia by altering the corneal geometry. This modification usually leads to an increase in higher-order optical aberrations compared to unoperated eyes. Consequently, implanting standard IOL in a previously operated eye may result in unpredictable and suboptimal refractive outcomes. The aim of this study was to quantify the performance improvement achieved by adding a free-form surface to a conventional EDOF implant in eyes that had previously undergone LASEK. A database of synthetic LASEK eyes was adapted to simulate pseudophakic eyes. The post-operative performances (refractive error and depth of field) for two types of EDOF IOLs were estimated using polychromatic VSOTF, in mesopic condition. The first one is a conventional refractive EDOF IOL, the second one is an identical lens incorporating a freeform surface on the posterior surface. Whether compared to the conventional IOL, the addition of a freeform surface allowed to significantly reduce the difference between the target refraction and subjective refraction. It also reduced the variation in depth of focus due to individual biometrics’ variations. A freeform surface may help compensate for higher-order aberration variations in LASEK eyes, improving both visual predictability and depth of focus.