Hyperopic LASIK and Postoperative Corneal Steepness: Revisiting the 49D Limit

Abstract

PURPOSE: To compare best-corrected visual acuity (BCVA) outcomes of hyperopic laser in-situ keratomileusis (LASIK) with a postoperative corneal steepness above versus below 49D. 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 two groups based on postoperative corneal steepness with steep corneas defined >49.0D and the control group ≤ 49.0D. Adjustments were performed to account for differences in baseline and intraoperative parameters. RESULTS: Overall, 1,703 eyes of 1,703 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 (44.6D vs 43.1D, p<0.001) and steep (45.1D vs 43.5D, p<0.001) keratometry, worse logMAR BCVA (0.07 vs 0.04, p=0.02) and higher sphere (4.9D vs 2.9D, p<0.001). Intraoperatively, they had a higher spherical treatment (4.6D vs 2.8D, p<0.001). Following hyperopic LASIK, the steep group had worse logMAR BCVA (0.10 vs 0.06, p=0.01). However, after accounting for differences in baseline and spherical treatment, no significant differences were found in postoperative logMAR BCVA (0.06 vs 0.06, p=0.99). The factors that remained associated with worse postoperative BCVA were higher spherical treatment (0.01 logMAR per 1D, p<0.001) and preoperative BCVA (0.60 logMAR per 1.00 logMAR, p<0.001). CONCLUSION: Postoperative corneal steepness greater than 49D is not associated with worse visual outcomes following hyperopic LASIK. However, lower preoperative visual potential and higher spherical treatment applied are associated with worse outcomes. The 49D cut-off should be revisited.