近视患者准分子激光原位角膜磨镶术前后明环境下对比敏感度分析

Photopic contrast sensitivity before and after LASIK surgery for myopes

目的测试低中度、高度近视患者在准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)前后明环境下的对比敏感度,评估其视觉质量变化。方法随机选取来我中心就诊的低中度、高度近视患者各38例(最佳矫正视力均达20/20)。由同一术者以博士伦217z系统对两组患者行常规标准LASIK手术。在明环境下,以CGT-1000分别对术前与术后第1个月、第3个月的对比敏感度进行检查。应用SPSS11.0软件对结果进行统计学分析。结果在明环境下,术前及术后第1个月和第3个月,在有眩光情况下,高度近视组对比敏感度均低于低中度近视组,差异有统计学意义(P<0.05);而在无眩光情况下,高度近视组对比敏感度在2.5、1.6、1.0、0.7deg这几个高频空间点上较低中度近视组低,差异有统计学意义(P<0.05)。两组患者在术后第1个月、第3个月时均出现对比敏感度下降,其中高度近视组下降更明显,差异有统计学意义(P<0.05)。两组的对比敏感度在术后第3个月时较术后第1个月时有所恢复。各组在各时段有眩光情况下对比敏感度均低于无眩光情况下对比敏感度,差异有统计学意义(P<0.05)。结论在明环境下,LASIK手术前后低中度近视患者对比敏感度均优于高度近视组;术后两组对比敏感度均较术前有所降低,高度近视组下降更为明显;对比敏感度随着时间推移有恢复趋势。

Objective To evaluate the constrast sensitivity between low or moderate myopes and high myopes under photopic conditions before and after laser in situ keratomileusis （LASIK） surgery. Methods Low or moderate myopes and high myopes were randomly selected and divided into two groups of 38 persons each. All the patients were examined and treated under regular clinical LASIK standards and guidelines by one surgeon with the same Technolas 217z Excimer Laser. The photopic contrast sensitivity of the two groups were checked before the operation and 1 month, 3 months after the operation using CGT-1000. Preoperative and postoperative parameters within and between the two groups were compared. Results Under glare conditions, the photopic contrast sensitivity of the high myopes was worse than that of the low or moderate myopes before and after surgery for each spatial frequency （P〈0.05）. The photopic contrast sensitivity of the high myopes with- out glare conditions was worse than that of the low or moderate myopes before and after surgery for 2.5, 1.6, 1, and 0.7 deg spa- tial frequencies （P〈0.05）. The within-subject contrast sensitivity comparisons in the two groups showed that there was a significant difference in photopic contrast sensitivity between pre- and post- operation in the high myopes （P〈0.05） but no significant difference was found in the low or moderate myopes. Under glare conditions, the photopic contrast sensitivity of both groups was worse than that under conditions without glare （P〈0.05）. Conclusion The photopic contrast sensitivity of low or moderate myopes is better than that of high myopes. After surgery, photopic contrast sensitivity for both groups are worse than preoperation levels, and even worse in high myopes. There is a tendency for photopic contrast sensitivity to recover, but a longer follow-up period is still needed.