Purpose
Color Visual Acuity (CVA) is the visual acuity that measures from colored Landolt ring on the background of achromatic color and that is the measure for evaluation of visual function for colors in daily life. In our previous research, we measured CVA of young normal subjects in the case of the background luminance of the color 30 [cd/m2] (same luminance with Landolt ring’s color) and 100 [cd/m2]. In the result, for the background luminance of 100 [cd/m2], CVAs of all colors were almost the same value; and for the background luminance of 30 [cd/m2], the CVAs of Blue-Yellow axis of color were higher than the other colors. Then, we further examined the changes of CVA for gradual changes of background luminance.
Methods
Four normal eyes of 4 subjects (4 males) were enrolled in this study. The mean age was 21.8 years old (range 21-22 years). They had no history of ocular disease (including color anomaly) or surgery. All of them had best corrected visual acuity of 20/13. We set the background color as white point of the standard light D65, and Ladnolt ring was colored with four colors (“Red” and “Green” for the Red-Green axis of color, “Green-Yellow” and “Blue-Purple” for the Green-Yellow axis of color) used in New Color Test (Luneau Ophtalmologie).The luminance value of Landolt ring was 30 [cd/m2] as a fixed value, and background was from 50 to 30 [cd/m2] and from 15 to 30 [cd/m2].
Results
There was significant difference for the colors of G (between 50 and 30 [cd/m2]), GY (between 50 and 30, 15 and 30 [cd/m2]), BP (between 50 and 30, 15 and 30, 15 and 28 [cd/m2]) (p<0.05, p<0.01, Friedman/Dunn test, shown in Figure)
Conclusions
In young subjects of normal eyes, it was confirmed that the influence of luminance difference between background and Landolt ring for the CVA of Blue-Yellow axis of color was significant that in comparison with the CVA of Red-Green axis of color. In addition, it was confirmed that there was a range of the background luminance that could measure the CVA without the influence of luminance difference between background and Landolt ring in the area of 30 plus or minus 2 [cd/m2].
Keywords: 471 color vision •
754 visual acuity