Comment on: Laser corneal enhancement after trifocal intraocular lens implantation in eyes that had previously undergone photoablative corneal refractive surgery.

Abstract

We congratulate Mayordomo-Cerdá et al. on their valuable observations in a large group of patients after sequential trifocal intraocular lens (IOL) implantation and laser corneal enhancement (LCE) after primary laser corneal refractive surgery (LCRS) for hyperopia or myopia.1 This is an increasingly frequent clinical problem as more patients with prior LCRS develop presbyopia and/or cataract yet still seek spectacle independence. We highlight some points of discussion, which may benefit the design of further studies aimed at optimizing outcomes in this challenging group. The reported rate of dissatisfaction of 10% to 20% is higher than that typically observed in studies of primary trifocal IOL implantation (∼2%).2 It would be interesting to know to what extent this disparity relates to residual refractive error or higher-order aberrations (HOAs): both are more likely after LCRS. Separating these factors may identify the main source of dissatisfaction and guide onward management of individual patients. A diffractive trifocal IOL adds negative spherical aberration to eyes with a wider defocus curve, which may be further modified by the original LCRS and subsequent LCE. While this may be desirable after myopic laser in situ keratomileusis (LASIK), it can have an adverse effect on quality of vision after hyperopic LCRS. The presentation of defocus curves may have facilitated the understanding of the presented outcomes, particularly in this relatively complex optical system. Furthermore, certain LCE techniques may be better suited to the original LCRS method used. Consequently, it would be of interest to know how HOAs varied between myopic and hyperopic subgroups after sequential treatments and correlation with final visual outcomes. As the number of post-LCRS patients with presbyopia and/or cataract increases, data on visual outcomes and safety are likely to increase across a range of treatment options such as monovision, small-aperture IOLs, or combination of trifocal and low-addition bifocal IOLs, with or without LCE.3 Alternatively, in the absence of cataract (45% in this study), additional LCE with or without presbyopic protocols may be considered instead of presbyopic refractive lens exchange. Since some degree of corneal multifocality is present after LASIK, especially with older laser protocols and myopic treatments, individuals with larger pupils may benefit from the spherical aberration–induced increased depth of focus. Current studies may yield more favorable results simply because lens technology has developed (ie, toric trifocal IOLs are now available), laser platforms have improved, and IOL calculation formulas for post-LCRS eyes have evolved.4,5 This study reported quite high cylindrical refractive error after primary LCRS for which toric trifocal IOL implantation may have prevented the need for subsequent LCE. The predominant method of LCE was photorefractive keratectomy (PRK) (72%), which is more likely to delay recovery with postoperative haze and ocular surface symptoms. Some surgeons favor LASIK or small-incision lenticule extraction for laser retreatments for these reasons. The preferred LCE protocol (topography-guided vs wavefront-guided treatment) is not clarified in the study, which could aid the interpretation of postoperative satisfaction. Information on LCE modality according to the type of primary treatment (myopic vs hyperopic) would also add further value to this welcome and valuable study.