视力表中E的尺寸

我在做一个实验，需要自制一张视力表，标准的视力表中各个E的尺寸是多少啊？

国际标准视力表 对数视力表 屈光度 E字的净大小mm
0.100020188 4.0 999.7981653 72.7074256
0.125915414 4.1 794.1839426 57.75472682
0.158514915 4.2 630.8554631 45.87713625
0.199554426 4.3 501.1164216 36.44224025
0.251219067 4.4 398.0589575 28.94768468
0.316259684 4.5 316.1958515 22.99442742
0.398139316 4.6 251.1683625 18.26549164
0.501217585 4.7 199.5141492 14.5090886
0.630982817 4.8 158.482921 11.52521138
0.794344269 4.9 125.89 9.154985603
1 5.0 100 7.272210345
1.2589 5.1 79.43442688 5.776638609
1.58482921 5.2 63.09828174 4.588639772
1.995141492 5.3 50.12175847 3.644959704
2.511683625 5.4 39.81393158 2.895352851
3.161958515 5.5 31.62596837 2.299906944
3.980589575 5.6 25.12190672 1.826917899
5.011164216 5.7 19.95544263 1.451201763
6.308554631 5.8 15.85149148 1.152753803

新旧视力表换算如下： 标准对数视力表 小数记录视力表 5.2 ------------------- 1.5 5.1 -------------------- 1.2 5.0 -------------------- 1.0 4.9 -------------------- 0.8 4.8 -------------------- 0.6 4.7 -------------------- 0.5 4.6 -------------------- 0.4 4.5 -------------------- 0.3 4.4 -------------------- 0.25 4.3 -------------------- 0.2 4.2 -------------------- 0.15 4.1 -------------------- 0.12 4.0 -------------------- 0