Impact of Nd:YAG Laser-Induced Pitting on Light Path Through Intraocular Lenses

Nd:YAG laser-induced pitting is a common complication of posterior capsulotomy, yet its effect on light propagation through intraocular lenses (IOLs) remains poorly understood. This exploratory, proof-of-concept experimental study evaluated the impact of Nd:YAG laser exposure on two hydrophobic acrylic IOL models by investigating both morphological damage and its optical consequences. Sixteen hydrophobic acrylic IOLs (eight CT LUCIA 621P, Carl Zeiss Meditec, and eight AcrySof IQ SN60WF, Alcon Laboratories), all with a power of +19.0 D, were mounted on a custom-designed holder; for each model, two lenses served as untreated controls and two lenses were exposed to 5, 10, or 15 standardized Nd:YAG laser applications (1.2 mJ per pulse). Laser-induced surface alterations were assessed using scanning electron microscopy (SEM), while changes in light propagation were analyzed by transmitting a low-power laser beam through each IOL onto a projection screen, acquiring the projected spot with a thermal imaging camera, and computing the intensity-weighted centroid of the spot in MATLAB. Nd:YAG laser exposure produced detectable surface damage in both IOL models, even after only five laser impacts. These structural alterations were associated with a measurable displacement of the transmitted beam centroid (Δpixel) in all treated lenses (mean values 11.1–11.8 pixels for CT LUCIA 621P and 12.4–19.2 pixels for AcrySof IQ SN60WF). Owing to the very small number of replicates (two lenses per condition), the different patterns observed in the two models should be regarded as exploratory trends rather than as evidence of material-dependent behavior. These findings suggest that inadvertent Nd:YAG laser-induced pitting can modify light propagation through the lens and highlight the importance of accurate posterior focusing and the use of the lowest effective laser energy during capsulotomy. To our knowledge, this is the first study to quantify laser-induced beam deviation after Nd:YAG pitting using thermographic centroid analysis. Further studies with larger samples, integrating optical bench measurements such as the modulation transfer function (MTF), point spread function (PSF), and wavefront analysis, are warranted to validate and extend these preliminary findings.