Abnormal perception of pattern-induced flicker colors in subjects with glaucoma.

Pattern-induced flicker colors (PIFCs) are subjective colors that can be elicited with rotation of an achromatic stimulus such as the Benham disk. The perceptive mechanisms underlying PIFCs are not well-understood, but are thought to be generated primarily by retinal cell types which may be dysfunctional in glaucoma. Using a custom computer-based system, we tested PIFC perception across several Benham disk parameters, including the rates of acceleration and deceleration, rotational direction, and image contrast in both control and glaucoma subjects. We defined the Benham perception limit (BPL) during acceleration as the rotational speed at which PIFCs were first detected (Benham perception limit for acceleration) and the BPL during deceleration as the rotational speed at which PIFCs were extinguished (Benham perception limit for deceleration). In general, we found that glaucoma subjects perceived PIFCs less frequently than control subjects. For all subjects, we found that slower rates of acceleration and deceleration resulted in a lower Benham perception limit for acceleration and a higher Benham perception limit for deceleration, suggesting that PIFCs were both more easily detected and extinguished. Finally, subjects with glaucoma required increased rotational speeds during acceleration to detect PIFCs under certain conditions. Further study is needed to determine if these findings can be used to enhance clinical detection strategies.