中低度近视患者LASIK术后散光矫正效果与视觉质量的关系

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

目的探讨中低度近视患者准分子激光原位角膜磨镶术(LASIK)后散光矫正效果与视觉质量的关系。方法选取行LASIK矫正近视合并散光的206眼,分为中低度散光组104眼和高度散光组102眼;术后3个月时,用标准矢量分析法评估LASIK对散光的矫正效果,评价指标包括预期散光矫正量(IRC)、手术引起的散光矫正量(SIRC)、散光大小的误差(EM)、散光角度的误差(EA)、矢量误差(EV)、误差率(ER)、矫正率(CR);手术前后在最佳矫正视力下,采用CSV-1000E对比敏感度仪检测明视无眩光时3、6、12、18 cpd空间频率下的对比敏感度函数(CSF),以评价视觉质量。结果术后3个月,高度散光组各空间频率的CSF低于术前(P均<0.01),中低度散光组12、18 cpd的CSF分别低于术前(P均<0.05),高度散光组的3、6、12 cpd的CSF低于中低度散光组(P均<0.05);中低度散光组的EV的绝对值(|EV|)小于高度散光组(P<0.05);高度散光组的|EV|与18 cpd的CSF呈正相关(r=0.629,P<0.01)。结论 LASIK术后3个月时,中低度近视合并高度散光患者可出现明视无眩光下CSF的下降,其中高频段CSF下降的原因可能与散光矫正的EV有关。

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 P 〈 0. O1 ）. 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 P 〈 0. 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 （P 〈 0. 05）. The ｜EV｜ of low to moderate astigmatism group was significant lower than that of high astigmatism group（P 〈0.05）. The ｜EV｜ of high astigmatism group was positively correlated with the 18 cpd CSF （r = 0. 629, P 〈 0. 01 ）. Conclusion There was decrease in CSF under photopia without glare of low to moderate my- opia with high astigmatism in 3 months post-LASIK. The decrease of high-frequency CSF may be associated with the astig- matism correction vector error.