The question, then, is how to relate viewing distance to a person's visualacuity.
现在的问题是,怎样将欣赏距离和人们的视觉灵敏度联系起来。
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Visualacuity - As part of the testing, you'll be asked to read letters on a distance chart. This test measures visualacuity, which is written as a fraction such as 20/40.