Optimization of intraocular lens constant improves refractive outcomes in combined endothelial keratoplasty and cataract surgery

Purpose: To evaluate the accuracy of intraocular lens (IOL) power calculations with A-constant optimization in Descemet's stripping automated endothelial keratoplasty (DSAEK) combined with cataract extraction and intraocular lens implantation (DSAEK triple procedure). Design: Retrospective case series. Participants: Thirty eyes of 22 patients with Fuchs' endothelial dystrophy who underwent the DSAEK triple procedure performed by a single surgeon. Methods: Prediction errors were calculated retrospectively for consecutive DSAEK triple procedures. These prediction errors then were used to determine an IOL constant for this cohort of patients. The new optimized IOL constant subsequently was compared with the manufacturer's IOL constant, allowing evaluation and quantification of refractive benefits of optimization. Main Outcomes Measures: The error in diopters (D) of the predicted refraction with the manufacturer's and optimized IOL constants. Results: Optimization of the A constant decreased the mean absolute error (MAE) from 1.09±0.63 D (range, 0.12-2.41 D) to 0.61±0.4 D (range, 0-1.58 D; P = 0.004). Comparing the intended and final postoperative refractions calculated with the original manufacturer's constant and the optimized constant, 20% versus 43% of all eyes were in the less than 0.5-D range and 50% versus 83% of all eyes were in the less than 1.0-D range of the target refraction. Furthermore, optimization decreased the number of eyes that were more than 1.0 D from the target refraction from 50% to 17%. Conclusions: Optimization of the IOL constant showed significantly improved accuracy of predicted postoperative refraction compared with the manufacturer's IOL constant, which may help improve the postoperative refractive outcomes in patients undergoing the DSAEK triple procedure. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.