Hyperopic LASIK and postoperative corneal steepness: Revisiting the 49-diopter limit

Purpose:To compare corrected distance visual acuity (CDVA) outcomes of hyperopic laser in situ keratomileusis (LASIK) with a postoperative corneal steepness above vs below 49 diopters (D).Setting:Care-Vision Laser Centers, Tel-Aviv, Israel.Design:Retrospective study.Methods:This study included consecutive patients who underwent hyperopic LASIK between January 2013 and December 2019. Hyperopic patients were divided into 2 groups based on postoperative corneal steepness with steep corneas defined >49.0 D and the control group ≤49.0 D. Adjustments were performed to account for differences in baseline and intraoperative parameters.Results:Overall, 1703 eyes of 1703 patients were included. Mean age was 48.3 ± 10.0 years, and 45.3% were male. Preoperatively, the steep group (2.4%, n = 41/1703) had steeper mean (44.6 D vs 43.1 D, P <.001) and steep (45.1 D vs 43.5 D, P <.001) keratometry, worse logMAR CDVA (0.07 vs 0.04, P =.02), and higher sphere (4.9 D vs 2.9 D, P <.001). Intraoperatively, they had a higher spherical treatment (4.6 D vs 2.8 D, P <.001). After hyperopic LASIK, the steep group had worse logMAR CDVA (0.10 vs 0.06, P =.01). However, after accounting for differences in baseline and spherical treatment, no significant differences were found in postoperative logMAR CDVA (0.06 vs 0.06, P =.99). The factors that remained associated with worse postoperative CDVA were higher spherical treatment (0.01 logMAR per 1 D, P <.001) and preoperative CDVA (0.60 logMAR per 1.00 logMAR, P <.001).Conclusions:Postoperative corneal steepness greater than 49 D is not associated with worse visual outcomes after hyperopic LASIK. However, lower preoperative visual potential and higher spherical treatment applied are associated with worse outcomes. The 49 D cutoff should be revisited.