Refractive Error After Phacoemulsification And Dmek Surgery In Fuchs Dystrophy: Can Topographic Parameters Help To Predict The Outcome?

Hyperopic shift error prediction remains a challenge in Fuchs patients undergoing cataract surgery and endothelial keratoplasty. Previous studies suggest a higher error in more severe cases and altered posterior cornea. We analyzed the frequency and magnitude of hyperopic refractive error after phacoemulsification and Descemet membrane endothelial keratoplasty (DMEK) depending on preoperative topography parameters in a retrospective case series of patients with Fuchs endothelial corneal dystrophy (FECD).

Fundación de Oftalmología Médica de la Comunidad Valenciana (FOM), Valencia, Spain. Cornea Unit.

Retrospective case series of patients with FECD who underwent cataract surgery and DMEK, either sequentially or as a triple procedure. Data from 19 eyes of 15 patients were collected. Preoperative topography values: posterior corneal asphericity (Q), central corneal thickness (CCT), and axial-sagital back-to-front ratio (RPA) were measured using Pentacam Scheimpflug imaging (Oculus, Germany). We studied the frequency and magnitude of the hyperopic shift in those eyes, considering as risk factors oblate corneas (posterior Q >0), preoperative CCT equal or higher than 600 microns, and RPA higher than 0.87. Sample was categorized into low (none or one risk factor) or high (two or three risk factors) risk groups.

To evaluate the hyperopic shift after the surgeries we recalculated the IOL power with the ESCRS calculator and compared it with the implanted IOL power. The mean hyperopic shift was 0.83 diopters +-0.3 SD (range -1,25D to +1,75D) 8 eyes had a hyperopic error equal or higher than 1D (75% of the high risk group and 25% of the low risk group). Of the other 11 eyes with a lower refractive error after surgery 45,5% were classified as high risk and 54,5% low risk). 54% of the eyes classified as high risk had a higher hyperopic error compared to 25% of the eyes of the lower risk group.

Preoperative topographic parameters might help deciding the IOL power target refraction in Fuchs patients undergoing cataract and DMEK surgery. Patients in the high risk group with a higher CCT, oblate cornea and/or RPA higher than 0.87 seem to have a higher hyperopic error after surgery, up to +1,75D, compared with patients without these risk factors. However, results are still vary variable in both groups. More studies with a larger sample and analyzing more topographic parameters could further improve refractive accuracy.