Limitations of OTF-based metrics for predicting through-focus visual acuity in pseudophakic eyes.

Predicting postoperative visual acuity (VA) from optical quality metrics is essential for the evaluation and development of intraocular lenses (IOLs). Metrics based on modulation transfer function (MTF) integration are commonly used but have important limitations: they neglect the phase of the optical transfer function (OTF) and fail to account for the distribution of contrast across spatial frequencies. As a result, they may overestimate visual performance-especially under defocus-by including phase-reversed or low-frequency contrast that contributes little to visual acuity. In this study, we measured the optical profiles of five IOLs using a new metrology device (NIMO-TEMPO), simulated their polychromatic through-focus OTFs, and computed several metrics, including MTF area, OTF area, visual Strehl ratio, and a perceptually weighted real part of the OTF (wOTF). These metrics were then correlated with through-focus VA curves extracted from publicly available FDA clinical trial data. Our results show that phase-sensitive metrics, particularly those that weight frequencies according to neural relevance, mitigate some of the limitations of conventional MTF-based approaches by suppressing spurious contrast and better reflecting the spatial content most relevant to VA. These findings highlight the need for physiologically meaningful, phase-aware metrics in both research and regulatory contexts.