机械法准分子激光前弹力层下角膜磨镶术治疗近视前后暗环境下的对比度视力与反应时间比较

目的 比较机械法准分子激光前弹力层下角膜磨镶术(SBK)治疗近视前后暗环境下对比度视力及反应时间的变化规律,评估术后视觉质量.方法 前瞻性病例自身对照研究.对行SBK手术治疗近视的患者20例(40眼),应用多功能电子视力测量仪(型号MFVA-100)测量术前、术后1个月、术后3个月暗环境暗背景下100％、25％、10％、5％4个对比度下的logMAR视力及反应时间.采用方差分析和q检验对获得的数据进行处理.结果 在暗环境暗背景下,随着对比度的下降,logMAR视力值呈增大趋势.在100％、25％对比度下,术前及术后不同时间段(1个月、3个月)对比度视力之间的差异有统计学意义(F=7.740、3.203,P均＜0.05).术后1个月、3个月与术前比较,logMAR视力值下降,差异有统计学意义(q=4.722、5.167,P＜0.05；q=3.000、3.217,P＜0.05)；术后1个月与3个月比较,差异无统计学意义(q=0.444、0.217,P＞0.05).在10％、5％对比度下,术前及术后不同时间段(1个月、3个月)对比度视力的差异无统计学意义(F=1.647、1.382,P均＞0.05).随着对比度的下降,反应时间呈延长趋势.在100％对比度下,术后1个月、3个月反应时间较术前缩短,术前、术后1个月、术后3个月三者之间差异无统计学意义(F=0.484,P＞0.05).在25％、10％、5％对比度下,术后反应时间延长,术前、术后1个月、术后3个月三者之间差异均无统计学意义(F=0.049、1.073、0.637,P均＞0.05).结论 机械法SBK治疗近视后,暗环境下100％、25％对比度视力提高,10％、5％对比度视力无显著变化,各对比度下反应时间无显著变化.SBK术后患者可获得良好的视觉质量,对比度视力和反应时间可作为评价SBK疗效的依据之一.

A study of visual acuity and reaction times of myopic patients at different contrast levels before and after sub-Bowman's keratomileusis

ObjectiveTo evaluate the changes in visual acuity and reaction times at different contrast levels in myopic patients before and after sub-Bowman′s keratomileusis （SBK）. MethodsThis was a prospective self-control study. A total of 20 patients （40 eyes） who had undergone SBK were enrolled in this study. LogMAR contrast visual acuity and reaction times were measured by the multi-functional visual acuity tester （MFVA-100） at 4 contrast levels （100%， 25%， 10%， 5%） with a dark background in a dark environment before surgery and 1 month and 3 months after surgery. Data were analyzed using ANOVA and SNK. ResultsAt the same room illumination， logMAR values gradually increased as contrast levels decreased. The postoperative logMAR values at 100% and 25% contrasts were significantly lower than preoperative values （q=4.722， 5.167， P<0.05； q=3.000， 3.217， P<0.05）， but the differences were not significant at 10% and 5% contrast levels （F=1.647， 1.382， P>0.05）. Reaction time increased with decreases in contrast levels. The postoperative reaction times became shorter at contrast levels of 100%， but were longer at 25%， 10% and 5% contrast levels. The differences were not significant （F=0.484， 0.049， 1.073， 0.637， P>0.05）. ConclusionAfter SBK， the logMAR values at 100% and 25% contrast levels were reduced， but there were no significant differences at 10% and 5% contrast levels. The surgery has no effect on reaction times at the 4 contrast levels. Myopic patients can acquire good contrast visual acuity in a dark environment after SBK. Contrast visual acuity and reaction time may be used as one of the bases to evaluate the effects of the surgery.