Clinical and simulated impact of intraocular lens tilt and decentration: from real-world data to optical simulation

To evaluate the optical impact of IOL tilt and decentration, we built synthetic eye models from real postoperative data and compared simulated image quality metrics with clinical outcomes. We included 105 eyes implanted with a monofocal aspheric IOL and measured their positioning using a tomographic device. With the clinical data we reconstruct each eye in Zemax optical software and evaluate four scenarios: aligned, decentered, tilted, and combined decentration and tilt. For each case, we calculated wavefront aberrations, three objective refractions, and predicted visual acuity from the intersection of the MTF and a threshold function. The average IOL tilt was 5.19 ± 1.28° and decentration was 0.25 ± 0.13 mm. Coma RMS increased from 0.00 µm in the aligned model to 0.26 ± 0.09 µm in the most altered scenario (p < 0.001), and VSX decreased from 0.80 ± 0.11 to 0.35 ± 0.17. Despite this optical degradation, BCVA remained unaffected, with a mean of 0.00 ± 0.05 LogMAR, and no significant correlation was found with tilt or decentration. The best agreement between simulated and clinical refraction was observed when both tilt and decentration were included. These results suggest that moderate IOL misalignment degrades optical quality without compromising visual acuity in monofocal IOLs, but further studies are needed for multifocal designs.