Abstract
Purpose :
Visual acuity reserve (VAR) (the ratio of a given print size to the print size at visual acuity threshold) is a critical parameter in determining real world reading ability. While visual acuity is widely used to evaluate visual function, VAR may vary across print of different languages. The purpose of this study is to evaluate VAR of Chinese newspaper characters in comparison to previously published data on U.S. newspapers (DeMarcos, 1997).
Methods :
Five sections (sports, weather, classified advertisements, syndicated columns and front-page articles) of five newspapers printed in simplified Chinese were evaluated. The height of the characters were measured independently by two investigators. The frequency of characters of six levels of complexity was also determined using a validated, published categorization scheme (Zhang, 2007). Finally, the VAR for each section was calculated from the ratio of print size measured in this study and published visual acuity thresholds for Chinese characters of aforementioned six levels of complexity. The VAR was calculated and compared between Chinese characters measured in this study and English letters previously reported.
Results :
Chinese characters in the newspapers ranged from 1.95 to 3.28 mm with medians of 2.78, 2.73, 2.14, 2.78 and 2.78 mm for sports, weather, classified, syndicated columns and front-page, respectively. English letters range from 1.0 to 2.0 mm with medians of 1.19, 1.28, 1.16, 1.67 and 1.74 mm for the corresponding sections. The ratio of print size between Chinese and English ranges from 1.60 to 2.34 in different sections. The frequency of Chinese characters from least complex to most complex was 34.2%, 17.0%, 15.7%, 12.0%, 7.2% and 13.9% in the sample newspapers. The visual acuity threshold across the six complexities of Chinese characters ranges from 4.62 to 5.93 arc minutes with a mean of 5.18 arc minutes (weighted for character frequency) compared to 3.37 arc minutes for the English letters. For Chinese newspapers, the VAR is 3.55 for the smallest median size and 4.61 for the largest median size at 40 cm. For US newspapers, the VAR is 2.96 and 4.44 for the smallest and largest median size, respectively.
Conclusions :
Although more complex, Chinese characters are larger than English letters in all sections of newspapers. This results in higher VAR, rendering them more legible than English newspapers in the U.S. This may impact reading ability comparison in clinical studies.
This is a 2020 ARVO Annual Meeting abstract.