In Vitro Optical Bench Assessment of an Extended Depth-of-Focus Intraocular Lens Based on Segmented Refractive Design

PURPOSE: To assess the in vitro optical performance of a low-addition segmented refractive intraocular lens (IOL) and compare it with extended depth-of-focus (EDOF) standards, monofocal IOLs, and high-addition bifocal IOLs manufactured from the same material. METHODS: Three identical material IOLs were assessed, namely a monofocal lens (HD), a low-addition multifocal lens (+2.00 diopters [D], SBL-2), and a high-addition multi-focal lens (+3.00 D, SBL-3). An optical bench measured the through-focus modulation transfer function (MTF) curves for 3- and 4.5-mm apertures. MTF values at five focal points (0 to -3.00 D) were evaluated. The area under the MTF curve was used to determine simulated visual acuity and depth of focus, compared to International Organization for Standardization (ISO) EDOF standards. Strehl ratio (SR) and United States Air Force (USAF) target imaging offered further quantitative and qualitative analyses. RESULTS: Through-focus MTF analysis confirmed distinct peaks corresponding to each IOL's design. The monofocal IOL provided the best distance (0 D) performance, whereas the low-addition IOL demonstrated the highest MTF values at intermediate foci (-1.50 to -2.50 D) and the high-addition IOL was superior at near (-3.00 D). The low-add IOL's depth of focus exceeded that of the monofocal IOL by 0.90 D at 0.20 logarithm of the minimum angle of resolution (logMAR), meeting the ISO EDOF standard. The monofocal IOL had the highest SR values. The USAF image indicated that the low-addition IOL provides stable image quality at intermediate focus, whereas the high-addition IOL excels at near focus. CONCLUSIONS: The low-addition IOL demonstrated superior intermediate optical performance compared with the monofocal and high-addition IOLs and fulfilled the ISO depth of focus criterion for EDOF IOLs. The high-addition IOL demonstrated superior optical performance at near focus.