Thursday Jan 17, 2008

Visual Acuity and Snellen Chart

In China, the Snellen chart used to measure visual acuity (VA) are full of tumbling E, having the opening pointing to all four directions, up, down, left and right. This is reasonable, as ordinary Chinese people do not know English decades ago. I believe this is better than the one used at US, because not all of Latin characters are equally recognizable. It is obvious that there's much more difference between an H and an O than an O and a D.

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