Relative legibility study using Chinese optotypes.

Traditionally, visual acuity test charts have been constructed using the English alphabet. It is desirable to have charts made in the native language of the Chinese and Asian populations. Previous efforts in this respect have not considered the relative legibility of Chinese optotypes. In this study, twelve Chinese optotypes were constructed according to the Snellen principle and subjected to a relative legibility trial. This study provides a basis on which Chinese optotypes of near-equal legibility may be selected.