Diffractive intraocular lenses reshape 577-nm retinal laser photocoagulation spots in a model eye

To evaluate whether diffractive intraocular lenses (IOLs) reshape 577-nm retinal laser photocoagulation spots in a model eye. A standardized model eye received 577-nm continuous-wave laser photocoagulation through a retinal contact lens at fixed settings: 200-µm spot, 100 mW, and 0.2 s. One monofocal IOL (ZCB00) and two diffractive IOLs (ZMB00, ZXR00) were tested in 15 sessions; a no-IOL condition provided power normalization and quality control. Delivered power was measured calorimetrically and normalized to no-IOL controls. Thermal-paper responses were threshold-segmented to quantify core fraction and disk area. Session-blocked models compared pooled r = 3 mm values; C-to-r = 3 mm changes were used to assess field-dependent effects. At pooled r = 3 mm, core fraction was 0.406 (95% CI, 0.382-0.430) for ZCB00, 0.179 (0.155-0.203) for ZMB00, and 0.201 (0.177-0.225) for ZXR00. Mean differences versus ZCB00 were - 0.227 (95% CI, - 0.261 to - 0.193) for ZMB00 and - 0.205 (- 0.239 to - 0.171) for ZXR00 (both Holm-adjusted P < 0.001). Disk area ratios versus ZCB00 were 0.754 (95% CI, 0.704 to 0.808) for ZMB00 and 0.682 (0.637 to 0.731) for ZXR00 (both Holm-adjusted P < 0.001). Normalized delivered power remained close to unity (0.993-0.997). C-to-r = 3 mm comparisons showed larger morphology changes for diffractive IOLs, whereas normalized delivered power changed little with radius. Under the specified 577-nm model-eye conditions, the tested diffractive bifocal and EDOF IOLs altered threshold-defined photothermal spot morphology relative to the monofocal control, while normalized aperture-integrated power remained near unity, suggesting field-dependent redistribution of target-plane irradiance.