Abstract:  Objective  To compare the variation of cornea Q -value and curvatures in three years after receiving aspheric LASIK or LASIK for a treatment of myopia. Design A retrospective comparative case series. Participants 155 patients (295 eyes) who underwent LASIK in Haerbin 242 hospital were chosen to participate in current study. Methods Patients were divided into two groups, aspheric LASIK group and conventional LASIK group. According to the corneal matrix reservation, each group were divided into three subgroups: group A＞350 μm, group B  300~350 μm and group C 280~299 μm. Q-value and anterior cornea curvatures were measured with Orbscan II topography system before and 1 week，1 month，6 month，1 year, 3 year after surgery． Main Outcome Measures The Q-value and anterior cornea curvatures. Results At the third year after surgery, the Q-value of patients who received aspheric LASIK group was group A 0.27±0.21, group B 0.33±0.31 and group C 0.93±0.19 respectively. The anterior cornea curvatures of the three groups was 39.6±1.17 D, 39.9±0.83 D and 0.93±0.19 D respectively. In the LASIK group, the Q-value was group A 0.35±0.24, group B 0.71±0.35 and group C 1.03±0.36 respectively. The anterior cornea curvatures was 40.2±0.98 D, 39.6±0.33 D and 37.3±1.83 D respectively, and the difference was not significant. Conclusion After 3 years' follow-up, aspheric profile could maintain the corneal aspherical shape better than conventional LASIK when the corneal matrix reservation was 300~350 μm. When the corneal matrix reservation was greater than 280 μm, both of these surgeries were safe. (Ophthalmol CHN, 2014, 23: 301-304) 

Key words: laser in situ keratomileusis, aspheric transition zone, Q-value, cornea curvatures