Abstract

Contrast vision and contrast adaptation have been extensively studied over the past 50 years. More than 1000 peer-reviewed articles have been published on this topic (PubMed 2014). Certainly, seeing contrast is a fundamental requirement for spatial vision. But there are major challenges: contrast vision should be possible over a huge range of illuminance to which we are exposed, and very low contrasts should be detectable over a wide range of spatial frequencies. The neural mechanisms mediating contrast vision should take into account that retinal image contrast is generally very low at high spatial frequencies, which contain the information about fine details and are therefore of particular importance for high visual acuity. This chapter tries to summarize some aspects of contrast vision, its limits, and what can be gained by contrast adaptation. Important earlier reviews on contrast vision and contrast adaptation were provided by Shapley and Enroth-Cugell (1984) and on visual adaptation by Kohn (2007). Many details described in their reviews are not recapitulated here. Since the topic is multifaceted, it is hoped that the preselection of aspects does not offend those researchers whose studies have not been mentioned due to space limitations. The figures include portraits of the authors when available.