Feasibility of Customized IOL Design: Pilot Study and Analysis
This study aims to determine the potential visual benefit of fully customized intraocular lens implant design based on preoperative scheimpflug corneal mapping using postoperative wavefront aberrometry.
Thirty consecutive patients without significant corneal, retinal or optic nerve disease scheduled for cataract surgery underwent detailed corneal mapping using a scheimpflug device. Phacoemulsification cataract extraction with implantation of an aspheric one-piece acrylic IOL was performed, selected as per usual practice. Patients with surgical or post-operative complications were excluded. At 3 months after surgery, total eye aberrometry was performed using a ray-tracing device. This was compared to the theoretical aberration profile calculated based on pre-operative corneal measurements as if a custom IOL had been inserted that was designed to minimize the corneal aberrations.
Preliminary results indicate that a significant (p<.05) reduction in total eye higher-order aberrations is theoretically possible by inserting a custom IOL. The theoretically ideal lens is designed using pre-operative corneal mapping to supplement standard third-generation IOL power prediction formulas based on axial length and average keratometry. There was no significant reduction of lower-order aberrations, namely spherical and first-order astigmatism. Limitations of the study are the need to determine the effective lens position preoperatively, and the requirement that the custom IOL be precisely centered and aligned with the visual axis.
This study demonstrates that a reduction in total higher-order aberration is theoretically possible using a custom IOL designed from preoperative corneal mapping. Extending beyond the current practice of a fixed aspheric adjustment in most standard IOLs, using a custom IOL could improve acuity and contrast sensitivity.