Color vision in the peripheral retina

Until recently, color vision in the peripheral field has been thought to be substantially less developed than color vision in the central field. Although the exact dimensions vary from study to study, most estimates of peripheral chromatic perception place the limit of trichromatic vision at no more than 30 degrees from fixation; the visual field is thought to be completely color blind at about 50 degrees of eccentricity. Within the last 10 years, an increased understanding of the changing spatial scale in the peripheral field has led researchers to reevaluate what is believed about peripheral function. We now know that virtually every measure of peripheral color perception can be improved by using a suitably large stimulus in the peripheral field. This paper examines current and past perspectives on peripheral color function, and describes two studies which demonstrate that peripheral and central chromatic processing are the same to the first order if the changes in spatial scale and photopic sensitivity with eccentricity are considered.