Excimer laser-assisted ex vivo model for eccentric keratoconus in human donor corneas.

PURPOSE: To develop a reproducible ex vivo model of eccentric keratoconus (KC) using a customized excimer laser ablation profile based on patient data, replicating the corneal morphology of ectatic disease.

METHODS

Human donor corneas were re-profiled using customized excimer laser shot files, based on tomography data from KC patients. Two distinct ablation patterns were applied to the anterior surface to create decentered steepening, and the posterior surface to obtain stromal thinning at the protrusion site. Corneal curvature and structural modifications were evaluated using tomographic and aberrometric analyses with Anterior Segment Optical Coherence Tomography (AS-OCT).

RESULTS

Laser surgical modeling produced a corneal profile consistent with typical KC morphology. Corneal thickness was significantly reduced, with a mean difference of 31.5 μm (p = 0.006), while anterior steepening was confirmed by an increase in Kmax from 50.252 to 58.023 D (p = 0.002). AvgK increased significantly, with a mean difference of 1.764 D (p < 0.001). Symmetry Index FRONT (SIF) rose significantly, from -0.257 to 3.759 D (p < 0.001), while corneal asphericity (Q-value) decreased from -0.752 to -1.337 (p = 0.06). Both ΔZFMax and ΔZBMax exhibited highly significant increases (p < 0.001). Significant increases were observed in higher-order aberrations (RMS) (p = 0.037) and coma (p < 0.001). Corneal analysis software classified the re-profiled corneas as KC.

CONCLUSION

This study introduced a novel ex vivo model of eccentric KC, using customized shot files for stromal reshaping through excimer laser ablation. By replicating the topographical and pachymetric features of keratoconic eyes, this model provides a reliable platform for exploring stromal augmentation techniques and reshaping effects, including customized lenticule implantation.