This prospective study found that adjusting preoperative keratometric (K) readings by −1.19 D led to accurate IOL power calculation and highly predictable refractive error in triple DSAEK.
While an important first step, the authors admit that the number 1.19 was chosen arbitrarily and future work will need to determine whether this number is optimal. Furthermore, even with this adjustment, a greater than 1D refractive surprise occurred in 17 percent of eyes. An important avenue of future study, therefore, is to evaluate which factors are associated with refractive surprises and determine whether nomograms need to be utilized in various clinical situations.
The authors assessed refractive error after triple DSAEK using adjusted K readings to calculate IOL power in 39 consecutive patients with Fuchs’ endothelial dystrophy and cataract. To calculate IOL power, preoperative K readings were reduced by 1.19 D. Posterior lamellae were prepared using a 300-μm head microkeratome.
The mean power of the implanted IOLs was 23.22 ± 2.90 D. The mean predicted and achieved refractions were −0.27 ± 0.26 D and −0.23 ± 0.73 D, respectively. The mean absolute prediction error was 0.59 ± 0.42 D (range, 0.05 to −1.52 D).
The postoperative spherical equivalent fell within ±0.50 D, ±1.00 D, and ±2.00 D of the predicted refraction in 55.5 percent, 83.3 percent and 100 percent of cases, respectively. Had the IOL power been calculated without adjusting the K readings, the mean absolute prediction error would have been significantly higher (0.86 ± 0.62 D; P = .04).