| PURPOSE:To compare the refractive outcomes, changes in higher order wavefront aberrations (HOAs), contrast sensitivity, corneal topography and cornea cutting depth after LASIK for myopia with Topography Supported Custom Ablation (TOSCA) and Aberration Smart Ablation (ASA) of the Carl Zeiss Meditec platform.METHODS:A randomized, prospective study of 111 myopic eyes without astigmatism of 60 patients undergoing LASIK surgery with the MEL80 excimer laser system was performed. Treatments were classified into two categories depending on the type of ablation algorithm used-TOSCA denoted eyes that underwent customized ablations based on corneal topography; ASA denoted eyes that underwent aspheric treatment zones. The mean preoperative spherical equivalent refraction was-5.00 diopters (D) (range:-1.50 to-10.75 D) in TOSCA group,-4.84 diopters (D) (range:-1.25 to-10.50 D) in ASA group. Follow-up data were reported at three month post-operatively.RESULTS:Three month after LASIK, the mean spherical equivalent refraction, uncorrected vision acuity (UCVA), total scotopic root-mean-square (RMS) HOAs, spherical aberration, coma aberration and the contrast sensitivity at 1.0,1.7,2.6,4.2,6.6 and 10.6 cpd (cycles per degree), between two groups were comparable, however, the theoretical cornea cutting depth (13.61±2.42μm/D Vs.19.40±5.23μm/D) in the TOSCA group were significantly less than that in the ASA group (p＜0.001), though the actual cutting depth was comparable (11.54±2.81μm/D Vs.12.12±3.18μm/D, p=0.180).CONCLUSIONS:TOSCA provides more accurate theoretical cutting depth than ASA. The treatments of myopia without myopic astigmatism in both groups are safe and effective.
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