本文件规定了一系列兰多特环视力类型，并描述了一种在明视条件下测量距离视力的方法，用于认证或许可。 本文件既不是临床测量的标准，也不是失明或部分视力的认证标准。 用于临床研究的其他光学类型见附录A，以供参考。交叉引用:ISO 3:1973ISO/TR 19498包含以下内容:修订，2020年2月

This document specifies a range of Landolt ring optotypes and describes a method for measuring distance visual acuity under photopic conditions for the purposes of certification or licensing. This document is neither intended as a standard for clinical measurements nor for the certification of blindness or partial sight. Other optotypes used for clinical investigations are described in Annex A for information.Cross References:ISO 3:1973ISO/TR 19498Incorporates the following:Amendment, February 2020