陆勤人员不同对比度视力和反应时间的研究

Study of visual acuity and reaction time at different contrast levels for military soldiers

目的研究正常视力的陆勤人员在不同对比度条件下,视力和反应时间的变化情况及其关系;评估特殊兵种选拔和征兵体检时,引入测量低对比度视力和反应时间的重要性。方法 54例(108眼)正常视力的现役陆勤人员,用多功能电子视力测量仪(MFVA-100)先后测试亮、暗背景下对比度为100%、25%、10%、5%时的logMar视力及反应时间。结果①相同背景亮度时,随对比度的下降各组视力呈下降趋势,低对比度组视力明显低于高对比度组(P<0.001);对比度相同时,暗背景组视力明显低于亮背景组(P<0.001)。②背景亮度相同时,随着对比度的下降各组的反应时间逐渐延长,亮背景下对比度10%组与5%组比较,差异无统计学意义(P>0.05),其余各组间差异均有统计学意义(P<0.05);暗背景下各组比较差异均有统计学意义(P<0.05);对比度相同时,暗背景组反应时间延长,在5%对比度水平差异有统计学意义(P<0.05),其余配对组之间差异无统计学意义(P>0.05)。结论正常视力的陆勤人员在亮背景下的视力优于暗背景,随着亮度和对比度降低,视力渐趋下降,个体差异增加,辨识物体的反应时间延长。应用MFVA-100测试不同对比度视力和反应时间,可以作为部队特殊兵种筛选和征兵体检时评估视功能的一种敏感而简便的辅助手段。

Objective To investigate the variation of visual acuity （VA） and reaction time （RT） at different contrast levels with bright and dark background and their relationship for military soldiers with normal VA, and to evaluate the importance of low contrast VA and RT measurement in personnel selection for special branches of the service and conscription physical examination. Methods Fifty-four active-duty army servicemen （ 108 eyes） with normal VA were enrolled, logMAR VA and RT were measured at four contrast levels （ 100% , 25% , 10% , 5% ） with bright and dark background in dark room with multi-functional visual acuity tester （MFVA-100）. The measurement values were divided into 8 groups according to the background and contrast level. Results ① VA of lower contrast group was significantly worse than that of higher contrast group （P 〈 0.001 ） with background luminance being identical. With contrast level descending, VA decreased gradually. At the same contrast level, VA of dark background group was significantly worse than that of bright background group （P 〈 0.001 ）.② RT extended gradually with contrast level descending with background luminance being identical. At bright background, there was no significant difference of RT between contrast 10% and 5% （P 〉 0.05）. However, significant differences were found among the others （ P 〈 0.05 ）. At dark background, RT of lower contrast group was significantly longer than that of higher contrast group（P 〈 0.05 ）. At the same contrast level, RT of dark background was longer than that of bright background, but only at contrast 5% level, there was significant diffe- rence（P 〈 0.05）. Conclusions The contrast VA of military soldiers with normal VA at bright background was better than at dark background. With luminance weakening and contrast descending, VA decreased individual variation increased, and the RT of stimulant recognition extended gradually. MFVA-100 offers a new sensitive, convenient adjunctive measure of contrast sensitivity which may be useful for identifying the unique visual abilities required for the military.