Having a maximal visual acuity of the better eye, after correction by refractive lenses, of one - tenth normal vision or less(20 / 200or less on the Snellen test.是什么意思_Having a maximal visual acuity of the better eye, after correction by refractive lenses, of one - tenth normal vision or less(20 / 200or less on the Snellen test.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句