Fundamental vision: A glaring case

Abstract

A brief history is given of the development of lighting design criteria. The reasons why a substantial proportion of the criteria are founded on implicit measures of the visual response are discussed. The current models of discomfort glare are given as an example. The successful application of the discomfort glare models is attributed to the ability of the visual system to adapt to a wide range of conditions. These models, it is argued, are not precise. As the discomfort glare models are apparently adequate for most practical purposes, the question 'Is there any need for change?' is addressed. A methodology founded on visual science is proposed for advancing an improved discomfort glare model. Visual channels are introduced; spatial adaptation is discussed as one visual mechanism which may contribute to discomfort glare. The paper concludes that two options are avaialble vis a vis discomfort glare: accept the status quo or develop a new model founded on understanding of the visual response. The latter choice will naturally lead to improved understanding of 'lighting quality'.