Purpose:
Human visual system mostly deals with chromatic color information rather than achromatic one. However, convetional subjective tests measuring visual function (e.g., visual acuity test, contrast sensitivity test) still uses achromatic color information. We aimed at developing new testing system of color visual function using personal computer and Liquid Crystal Display ColorEdge CG245W (NANAO Co.). We adoptedLandolt ring as a target that can be arbitrarily set colors, presenting time, size and direction. We investigated the color reproducibility of this system, and the feature of color visual function in normal eyes of young subjects.
Methods:
First of all, we measured the colors to use for test (Figure) by spectroradiometer CS-2000 (KONICA MINOLTA Co.). The measured values were compared with target values using color difference CIELAB. Secondly, 6 eyes of 6 normal subjects (6 female, 20 to 23 years old) were examined using this system. They had no history of ocular disease (including color anomaly) and ocular surgery. All of them had good best corrected distance visual acuity 20/13 or better than 20/13. We set the presenting time of target for 5[s], and measured visual acuity with 15 colored Landolt rings, and evaluated the average visual acuity (LogMAR) for each colors in each age group.
Results:
The mean color difference between measured and target values (include white point D65) was 0.91±0.3. The measurement result of LogMAR for 15 colors had significant difference (P<0.001 : Friedman test). The most negative LogMAR (better visual acuity) was GB and R (red/green channel). By contrast, the most positive one (worse visual acuity) was BP and GY (yellow/blue channel).
Conclusions:
Since the evaluation of color measurement on LCD was graded as "slight" by National Bureau of Standards (NBS), this testing system could be used for color visual acuity test. Moreover, this system could be useful to evaluate cone function, because the result showing that the LogMAR value of yellow/blue channel color was positive represents S-cone characteristics that the number of S-cones is much less thanother cone (L, M). In the future, new insights may be obtained using this system in various ocular diseases.
Keywords: color vision • visual acuity • clinical (human) or epidemiologic studies: systems/equipment/techniques