LASIK术后夜间视觉质量与角膜非球面性关系的研究

The relationship of night vision quality and corneal asphericity after LASIK surgery

目的分析准分子激光原位角膜磨镶术(LASIK)术后夜间视觉质量与角膜非球面性变化的关系。设计回顾性病例系列。研究对象在2007年9月至12月期间行LASIK手术的患者中,顺序选取术前最佳矫正视力(BCVA)≥1.0,术后裸眼视力≥1.0,随访资料完整患者72例(144眼),等效球镜度数-4.0～-8.0 D,平均(-5.80+1.04)D。方法术前及术后3个月行Orbscan检查、K/Q值、Mesotest暗视条件下对比敏感度检查。主要指标暗视下无眩光Mesotest对比敏感度通过等级、Q值。结果Mesotest对比敏感度检查:无眩光暗视条件下,术后3个月未通过各等级测试的例数比术前增加,72例患者中26例对比敏感度等级比术前降低1～2个等级。Q值的分布:术前平均(-0.16+0.12),术后3个月平均(0.49+0.24),差异有统计学意义。直线相关回归分析:术前与术后Q值差值与对比敏感度等级变化呈正相关(回归方程为y=0.068x+0.5965,pearson系数r=0.476,P=0.000, P<0.01)。结论LASIK术后暗环境下对比敏感度降低与角膜Q值改变有关,角膜前表面非球面性改变是影响LASIK术后夜间视觉质量的重要因素之一。

Objective To evaluate the relationship between night visual quality and corneal asphericity after LASIK surgery. Design Retrospective case series. Participants 144 eyes of 72 patients who were going to accept LASIK surgery in Changhai Hospital from September to December in 2007. The enrolled criteria involved preoperative best corrected visual acuity （BCVA） 1.0 or more, and postoperative uncorrected visual acuity （UCVA） 1.0 or more, at least 3 months followed-up. Spherical equivalence -4.0 D- -8.0 D. Methods Preoperative and postoperative examinations included mesopic contrast sensitivity, Orbscan, K/Q value. Main Outcome Measures To discriminate the mesopic contrast limits of grade under mesopic condition without glare, Q value Results The Mesotest results： compared to preoperatively, on the 3rd month postoperatively under Mesopic condition without gjare the proportion of patients unable to discriminate the mesopic contrast limits of grades rose and the contrast limits were degraded one or two grade in 26 patients. Q value： the average of Q value before LASIK was -0.16±0.12 and 3 months after LASIK was 0.49±0.24, there was statistical significance. The change of contrast sensitivity has positive correlation with the change of Q value after LASIK （y= 0.068x ＋ 0.5965,r=- 0.476,P=0.000, P〈0.01 ）. Conclusions The decrease of mesopic contrast sensitivity is related to the change of corneal Q value, the change of corneal aspherieity is one of the important factors which influence the night vision quality after LASIK