Relationship between the correction effect of astigmatism with low to moderate myopia by LASIK and the visual quality

Objective To investigate the correction effect of astigmatism with low to moderate myopia by LASIK and the relationship between the effect and visual quality.Methods A total of 206 myopic eyes with astigmatism were treated by LASIK,which were divided into low to moderate astigmatism group(-0.75 D~-2.25 D) of 104 eyes and high astigmatism group(-2.50 D to-4.00 D) of 102 eyes.Three months later after the operation,the effect of astigmatism correction was evaluated by the standardized vector analysis,which was represented by IRC(intended refractive correction),SIRC(surgically induced refractive correction),EM(error of magnitude),EA(error of angle),EV(error vector),ER(error ratio) and CR(correction ratio).To evaluate the visual quality,the photopic CSF without glare was examined by CSV-1000E under 3,6,12 and 18 cpd spatial frequencies.Results Three months later,the CSF of all spatial frequencies of high astigmatism group were significant lower than those preoperatively(all P0.01).The CSF of spatial frequencies 12 cpd(cycles per degree) and 18 cpd of low to moderate astigmatism group were significant lower than those preoperatively(all P0.05).The CSF of 3 cpd,6 cpd and 12 cpd of high astigmatism group were significant lower than those of low to moderate astigmatism group(P0.05).The |EV| of low to moderate astigmatism group was significant lower than that of high astigmatism group(P0.05).The |EV| of high astigmatism group was positively correlated with the 18 cpd CSF(r=0.629,P0.01).Conclusion There was decrease in CSF under photopia without glare of low to moderate myopia with high astigmatism in 3 months post-LASIK.The decrease of high-frequency CSF may be associated with the astigmatism correction vector error.