| 目的 按照Weber-Fechner法则设计科学合理的视力表和记录方法。
方法 采用三划等长的E形视标，视标大小及排列采用均匀的几何增率，每行视标数为4个,共14行，每两行视标变化进率为10√10。视力检查距离是为3米。视力记录可选择视角对数记录、小数记录、分数记录和五分记录。
结果 该视力表纠正每行之间视标个数不等和大视标个数较少的缺点，采用多种视力记录方法，并可以作多种视力记录的相应数值的转换。
结论 本标准化LogMAR对数视力表具有视力统计方便、准确优点，在临床、教学和科研工作上具有重要意义。
Objective To design a scientific and reasonable visual acuity chart and scores based on Weber-Fechner law.
Methods We used the tumbling E optotype on this chart. The space between letters is one letter wide and the space between lines is equal in height to the letters of the next lower line. The progression of letter height from line to line is geometric. This multiplier is the tenth root of ten, or 0.1 log unit. We used four letters per line.There are 14 lines on this chart. The testing distance is 3m. The visual acuity score can be recorded as logarithmof the minimum angle of resolution(logMAR) notation, decimal notation,Snellen fraction notation or five-cent notation.
Results Using this LogMAR visual acuity chart eliminates the deficiencies of different number of optotypes on each line and fewer optotypes at the largest size level of current charts. Conversion for visual acuity notations is very convenience in this chart.
Conclusion Measurements of visual acuity using this chart provide reproducible visual acuity information which facilitates quantitative data analysis.
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