Flickering patterns can be uncomfortable for normal observers and may even produce epileptic seizures in photosensitive observers. These adverse effects are aspects of “visual discomfort.” To avoid inducing visual discomfort, exploring the underlying mechanisms contributing to discomfort from a source of flicker is important from a scientific perspective and an applied perspective. In this review, the recent literature examining the effects of amplitude and phase spectrum, adaptation, and ambient light level on discomfort from flicker is summarized. The involvement of low-level and higher-level visual processing in visual discomfort in the temporal domain is discussed. Several unsolved problems are also outlined for future studies.
