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.

Date Published: 11 February 2008
PDF: 8 pages
Proc. SPIE 6844, Ophthalmic Technologies XVIII, 68441R (11 February 2008); doi: 10.1117/12.762896

Published in SPIE Proceedings Vol. 6844:
Ophthalmic Technologies XVIII
Bruce E. Stuck; Fabrice Manns; Per G. Söderberg; Michael Belkin M.D.; Arthur Ho, Editor(s)