Cataract and Optometrists Meeting

Biography

Biography: Lily Karmona

Abstract

Purpose: To compare the surgically induced astigmatism by H-LASIK vs. M-LASIK in patients with no pre-operative refractive astigmatism. Methods: A retrospective study of patients who had H-LASIK and M-LASIK during 2005-2014 at the Care-Vision Laser Center, Tel-Aviv, Israel. We calculated the mean absolute surgically induced astigmatism and performed risk factor analysis for induced astigmatism of more than 0.5 D. Differences between H-LASIK and M-LASIK were analyzed. Results: 3877 eyes that underwent M-LASIK and 549 eyes that had H-LASIK were non-astigmatic pre-op, received a non astigmatic treatment and met the inclusion criteria. The mean age of the patients was 32.8±19.7 SD (range 17-55 years). The induced astigmatism was determined by the post-op manifest refraction astigmatism as all cases were non-astigmatic preoperatively. 6 months after surgery, hyperopic treatment induced more SIA than myopic treatment: the mean induced astigmatism was 0.49±0.48 D in the H-LASIK group and 0.36 D±0.4 in the M-LASIK group (P<0.001). In the H-LASIK group, the risk factors for induced astigmatism of >0.5 D were: younger age (47.8±9.9 years old vs. 49.8±8.2 years old; p=0.05), higher pre-operative refractive error (p=0.003) and larger treated optic zone (7 mm vs. 6 mm). In the M-LASIK group, eyes with SIA tended to have steeper corneas (43.8±1.5 D vs. 43.6 ± 1.4 D; p=0.001), higher refractive spherical equivalent (3.43±1.53 vs. 3.07±1.45 p<0.001) and smaller treatment optic zones (6 mm vs. 7 mm). Conclusion: There was a consistent trend toward more SIA in hyperopic LASIK vs. myopic LASIK, and in higher refractive error correction. In H-LASIK we found larger optic zones to induce more SIA and in M-LASIK we found smaller ones to cause it.