Landolt rings have been used by ophthalmologists to evaluate visual acuity for nearly a hundred years [6].

近一百年来兰杜特环被眼科医生视为用于评价视敏度[6]。

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Landolt rings have been used by ophthalmologists to evaluate visual acuity for nearly a hundred years [6].

近一百年来兰杜特环被眼科医生视为用于评价视敏度[6]。

youdao