准分子激光前弹力层下角膜磨镶术前后散射特征及相关因素分析

目的 研究准分子激光前弹力层下角膜磨镶术（SBK）矫正屈光不正手术前后的散射特征，并分析其相关因素。方法 前瞻性临床研究。行SBK手术的近视及近视散光患者46例（92眼），男29例，女17例，年龄18～39岁，平均（24.0±5.4）岁；等效球镜度为-4.75～-11.13 D，平均（-6.70±1.50）D；散光度为0～2.50 D，平均（0.68±0.58）D。手术前，采用Pentacam眼前节分析仪测量平均曲率值、角膜中央厚度等。手术前及手术后第1天、第1周、第1个月，应用C-Quant散射光计量仪测量患者的散射值。对所得数据分别应用重复测量的方差分析、配对t检验及Pearson相关进行分析。结果 SBK手术前眼内散射光计量值平均为0.90±0.13，手术后第1天、第1周、第1个月眼内散射光计量值分别为0.96±0.13、0.98±0.10、0.99±0.09，与术前比较，术后各个随访时间点散射均增加（F=24.94，P＜0.05）。经Pearson相关分析，手术前散射光计量值与等效球镜度、平均曲率值、角膜中央厚度的相关性无统计学意义；手术后各时间点散射光计量值增加量与术前散射光计量值水平呈负相关（r=-0.47、-0.67、-0.78，P均＜0.05），与术前等效球镜度、切削深度的相关性无统计学意义。结论 SBK术后早期散射增加可能是影响视觉质量的因素之一，术前散射光计量值愈低的患者术后增加量愈明显。

Characteristics of straylight and relevant factors analysis in myopia before and after sub-Bowman′s keratomileusis

Objective To investigate the characteristics and relevant factors of intraocular straylight before and after sub-Bowman′s keratomileusis (SBK). Methods This was a prospective clinical study. Straylight measurement was performed on 46 myopic and myopic astigmatism patients (92 eyes) before SBK surgery and 1 day， 1 week， and 1 month after surgery using Oculus C-Quant straylight meter. In 46 patients， there were 29 males and 17 females， the mean age was (24.0±5.4)years (range： 18 to 39 years)， and the mean preoperative spherical equivalent (SE) of refraction was (-6.70±1.50)D (range： -11.13 to -4.75 D)， with mean astigmatism of (0.68±0.58)D (range： 0 to 2.50 D). The mean keratometric value and central corneal thickness (CCT) were tested by Pentacam device. The data was analyzed for statistical significance by repeated measure ANOVA， paired t tests and Pearson correlation using SPSS 13.0 software. Results Patients had a mean straylight of logarithmic value of the straylight parameter log(s)]=(0.90±0.13) before surgery， which showed no significant correlation with spherical equivalent (SE)， keratometric (K) value， and CCT. After surgery， the mean straylight of log(s)]=0.96±0.13， 0.98±0.10， and 0.99±0.09 at 1 day， 1 week， and 1 month postoperatively respectively. When comparing with preoperative straylight values， the difference did reach a statistical significance increase for various time points after SBK (F=24.94， P＜0.05). The individual postop-preop changes in straylight showed significant negative correlation with the preoperative values (r=-0.47， -0.67， -0.78， P<0.05)， and showed no significant relationship with intended refractive correction and ablation depth. Conclusion Straylight values increases significantly at early time after SBK， which maybe influence visual performance at this time. Patients with lower preoperative straylight values present exacerbated elevation after SBK.