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

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Fuchs' endothelial corneal dystrophy (FECD) presents challenges for intraocular lens (IOL) power calculation during combined cataract surgery and Descemet membrane endothelial keratoplasty (triple-DMEK).
• Accurate IOL power calculation is crucial for achieving desired refractive outcomes after triple-DMEK.
• Predicting post-operative corneal power changes is essential for optimizing IOL selection.

Purpose of the Study:

• To enhance the accuracy of IOL power calculation in triple-DMEK by predicting post-operative corneal power changes.
• To develop and validate a novel model for predicting corneal changes after triple-DMEK.
• To compare the predictive accuracy of the new model with traditional IOL optimization methods.

Main Methods:

• An observational ambispective monocentric cohort study was conducted.
• A linear corneal change model (LCCM) was developed using the preoperative corneal ratio (anterior/posterior radius) to predict corneal power changes.
• LCCM prediction errors were compared against a traditional IOL optimization method for validation.

Main Results:

• The study analyzed 97 eyes from 69 patients undergoing triple-DMEK.
• Significant median changes in simulated keratometry (SimK) of -0.21 D and total keratometry (TK) of -0.62 D were observed post-surgery (p < 0.001).
• The LCCM demonstrated comparable mean absolute error (MAE) to the constant optimization method but showed a lower MAE (1.87 D) compared to the optimization method (2.08 D).

Conclusions:

• Corneal power (SimK and TK) significantly changes after triple-DMEK.
• The LCCM aids surgeons in selecting the appropriate IOL by predicting corneal changes, potentially reducing refractive surprises.
• Further research is recommended due to FECD severity variability and limitations of standard biometric formulas in non-standard eyes.