Induced De Novo Astigmatism After Hyperopic LASIK Versus Myopic LASIK Surgery in Nonastigmatic Eyes.

Abstract

PURPOSE To compare the astigmatism induced surgically (SIA) by spherical hyperopic laser in situ keratomileusis (H-LASIK) versus myopic laser in situ keratomileusis (M-LASIK) in nonastigmatic eyes. METHODS A retrospective study of patients who underwent LASIK surgery between 2005 and 2014 at the Care-Vision Laser Center, Israel. We calculated the mean absolute SIA and performed risk factor analysis for induced astigmatism. Differences between H-LASIK and M-LASIK were analyzed. RESULTS Eyes of 3877 patients who underwent M-LASIK and of 549 patients who underwent H-LASIK were nonastigmatic preoperatively and received a nonastigmatic treatment. Three months after surgery, hyperopic treatment induced more SIA (0.49 ± 0.48 D) than did myopic treatment (0.36 ± 0.4 D) (P < 0.001). In the H-LASIK group, the risk factors for induced astigmatism of >0.5 D were a higher preoperative refractive error (P = 0.003) and larger optical zone (7 vs. 6 mm). In the M-LASIK group, eyes with SIA >0.5 D tended to have steeper corneas preoperatively (43.8 ± 1.5 vs. 43.6 ± 1.4 D; P = 0.001), a higher spherical equivalent (-3.43 ± 1.53 Vs. -3.07 ± 1.45 P < 0.001), and smaller treatment zones (6 vs. 7 mm). In H-LASIK, the mean induced astigmatic axis was at 74.6 degrees. CONCLUSIONS There was a consistent trend toward more SIA in H-LASIK and in higher refractive error correction. In H-LASIK larger optical zones induce more SIA and in M-LASIK smaller ones caused it.

DOI: 10.1097/ICO.0000000000001253

Cite this paper

@article{Karmona2017InducedDN, title={Induced De Novo Astigmatism After Hyperopic LASIK Versus Myopic LASIK Surgery in Nonastigmatic Eyes.}, author={Lily Karmona and Michael Mimouni and Igor Vainer and Tzahi Sela and Gur Munzer and Igor Kaiserman}, journal={Cornea}, year={2017}, volume={36 9}, pages={1040-1043} }