Optimizing IOL calculation in triple-DMEK: Data from a real-life cohort

Purpose

To enhance the accuracy of intraocular lens (IOL) power calculation in patients with Fuchs’ endothelial corneal dystrophy (FECD) undergoing simultaneous cataract surgery and Descemet membrane endothelial keratoplasty (triple-DMEK) by predicting corneal power changes.

Methods

Observational ambispective monocentric cohort study. A linear corneal change model (LCCM) was developed to predict corneal change from the preoperative corneal ratio (anterior/posterior radius). LCCM was validated by comparing prediction errors with the traditional IOL optimization method.

Results

97 eyes of 69 patients were analyzed. Preoperative keratometry was biometrically unmeasurable in 9 eyes, so manually entered autorefractometer data were used for IOL calculations and were analyzed separately. Mean absolute error (MAE) in the manual group (1.35 D (-1.04, 3.75)) was higher than the measured group (0.75 D (-0.62, 2.12)). The median change in simulated keratometry (SimK) was -0.21 ± 0.68 D and in total keratometry (TK) was -0.62 ± 1.09 D (p < 0.001). SRKT outperformed the rest with constant optimization (0.60 D (-0.53, 1.74)). LCCM showed similar MAE to the constant optimization method (p > 0.05). However, MAE for the optimization method was higher (2.08 D (1.77, 2.39)) than LCCM method (1.87 D (1.62, 2.12)).

Conclusions

SimK and TK change significantly after Triple-DMEK. The LCCM could reduce extreme refractive surprises by assisting surgeons in the individualized selection of the best IOL for each eye based on the expected corneal change. Study limitations include variability in FECD severity and the inherent limitations of biometric formulas applied to non-standard eyes. Further studies are recommended.