| 摘要: |
| 目的：观察正常人眼在亮、暗背景下不同对比度的视力变化.方法：54例（108眼）正常视力的成年男性,用多功能电子视力测量仪（MFVA-100）比较亮、暗背景下不同对比度（100%、25%、10%、5%）的logMAR视力,并分析亮、暗背景下视力的相关性.结果：背景亮度相同时,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）.亮背景100%对比度组视力与暗背景各组视力之间均无线性相关,与亮背景25%、10%、5%对比度组视力呈正线性相关（P＜0.001）;暗背景100%对比度组与暗背景25%、10%、5%对比度组视力呈正线性相关（P＜0.001）.随着对比度的降低,各组视力的波动幅度增加,暗背景下对比度5%时差异最大.结论：正常人眼亮背景下的视力优于暗背景,随着对比度降低,视力渐趋下降,个体差异增加,亮、暗背景之间的视力变化无线性相关. |
| 关键词: 背景 视力 对比度 |
| DOI：10.3724/SP.J.1008.2007.00714 |
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| 基金项目: |
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| Changes of visual acuity at different contrast levels under bright and dark backgrounds in healthy adults |
| SHI Sheng , LIU Lin , ZHOU Xing-tao , BAO Lan , XIAO Qi-rui |
| (1. Department of Ophthalmology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China; 2. Department of Ophthalmology, No. 85 Hospital of PLA , Shanghai 200052; 3. Department of Ophthalmology, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031) |
| Abstract: |
| Objective： To investigate the variation of visual acuity （VA） at different contrast levels under bright and dark backgrounds in healthy adults. Methods： Fifty-four men （ 108 eyes） with normal VA were enrolled in this study. LogMAR VA was measured at 4 contrast levels （100 %, 25 %, 10%, and 5 % ） under bright and dark backgrounds with multi-functional visual acuity tester （MFVA-100）. The relationship of VA between bright and dark backgrounds was analyzed. Results： （1） Subjects with lower contrast level had significantly worse VA than those with higher contrast level when the background was identical （P〈0. 001）; VA decreased gradually with the decrease of contrast level. At the same contrast level, the VA under dark background group was significantly worse than that under bright background group （P〈0. 001）. （2） The VA at contrast level 100% under bright background was not linearly related to those under dark background （P〉0.05）, but was linearly related to those at other contrast levels under bright background （P〈0. 001）. Under dark background, the VA at contrast level 100% was linearly related to those at other contrast levels（P〈0. 001）. （3） The fluctuating differences （log unit） of VA increased with the decrease of contrast level, with the maximal difference found at contrast level 5 ; under dark background. Conclusion： The VA of healthy men under bright background is better than that under dark background. The VA decreases and individual variation increases gradually with the decrease of contrast level. There is no linear correlation of VA between the bright and dark backgrounds. |
| Key words: background visual acuity contrast |
