The color contrast capability was investigated for 3 volunteers with 7 specially developed test charts in red, green, blue,
cyan, magenta, yellow and black as a reference, namely without and after glare from 4 colored high-brightness LEDs.
Each subject completed 56 tests in order to check especially the ability to discriminate low contrast.
It was found that a contrast decrease of one level is equivalent to an increase of about 4 s in the required identification
time and in addition a delay time between about 14 s and 16 s has been measured at the beginning of the respective test
as a result of the dazzling glare from an LED.
In addition trials have been performed with 4 different pseudoisochromatic color plates designed by Ishihara for color
vision. These plates have been used to determine temporary color deficiencies after an exposure from a high-brightness
LED. For this purpose 40 volunteers have been included in a laboratory test. Color vision was impaired for periods
between 27 s and 186 s depending on the applied color plate and respective LED color.