Standardization of national visual acuity chart

Visual acuity chart is extremely important and a very useful tool in enrollment,recruitment,screening,ophthalmology clinic and scientific research.So far,the design of visual acuity chart has been more and more mature,and the core design has basically trended to be standard.However,people are still confused about the selection,design and application of visual acuity chart.This paper reviewed the development history,core design and practical problems of international and national visual acuity charts,in order to avoid the misunderstandings in selection and application of visual acuity chart effectively,and make it to be better used in the screening,ophthalmology clinic and scientific research. Key words: Standardization;  Visual acuity;  Visual acuity chart;  Increasing rate