Abstract
For a reliable visual test, it is important to evaluate the legibility of the symbols, which depends on several factors. Previous studies have compared the legibility of Latin optotypes. This study developed a visual function test based on identification visual capacity for a Chinese reading population. The legibility of word symbols was assessed with three methods: (1) Identification of the contrast thresholds of the character sets, (2) patterns of confusion matrices obtained from analysis of the frequency of incorrect stimulus/response pairs, and (3) pixel ratios of bitmap images of Chinese characters. Then characters of similar legibility in each character set were selected. The contrast thresholds of the final five character sets and the Tumbling E and Landolt C optotypes were evaluated. No significant differences in contrast threshold were found among the five selected character sets (p > 0.05), but the contrast thresholds were significantly higher than those of the E and C optotypes. Our results indicate that combining multiple methods to include the influences of the properties of visual stimuli would be useful in investigating the legibility of visual word symbols.
Highlights
A typical visual function test usually uses simple, standardized visual optotypes to examine the visual capacity of patients[1,2]
It is possible to use the Landolt C or Tumbling E charts for people who cannot read Latin optotypes by instructing the patients to respond to the orientation of the gap in an E or C, and quite a number of studies support the relationship between the visual acuity and functional vision performance[6,7]
Landolt C optotypes.We demonstrated the identification contrast threshold according to their original character sets
Summary
A typical visual function test usually uses simple, standardized visual optotypes to examine the visual capacity of patients[1,2]. It is possible to use the Landolt C or Tumbling E charts for people who cannot read Latin optotypes by instructing the patients to respond to the orientation of the gap in an E or C, and quite a number of studies support the relationship between the visual acuity and functional vision performance[6,7]. One classical approach to assess the legibility of visual symbols, as used in the development of the Sloan letter chart[1,13,15,16], is to compare the percentage of correct responses for each optotype in an optotype set and to conduct an error analysis of the incorrect responses at the limit of visual acuity or contrast threshold. It is necessary to consider the performance near the contrast threshold when assessing legibility
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
