paper Despite nearly a century of research, we are still unable to accurately predict discomfort due to glare.

The vast majority of discomfort glare research uses subjective evaluations – primarily category rating or luminance adjustment. This article discusses methodological issues which contribute to uncertainty in evaluations.

Fotios S. Research Note: Uncertainty in subjective evaluation of discomfort glare. Lighting Research and Technology, 2015; 47(3); 379-383.

paper It is unlikely that the commonly used procedures will ever reach resolution. This article raised suggestions for alternative procedures.

Fotios S. Correspondence: New methods for the evaluation of discomfort glare. Lighting Research and Technology 2018; 50(3): 489-491.

paper Evaluations of discomfort using category rating were compared against involuntary physiological responses.

Subjective evaluation of discomfort was highly correlated with eye movement and pupil constriction: Severe glare discomfort increased the speed of eye movement and caused larger pupil constriction.

Lin Y, Fotios S, Wei M, Liu Y, Guo W, Sun Y. Eye movement and pupil size constriction under discomfort glare. Investigative Ophthalmology and Visual Science, 2015; 56(3); 1649-1656.

paper A series of experiments were conducted to explore the influence of variations in experimental design, the aim being to explain the variance between different studies.

In this first experiment we explored the influence of anchor bias in luminance adjustments.

Kent M, Fotios S, Altomonte S. Discomfort glare evaluation: The influence of anchor bias in luminance adjustments. Lighting Research and Technology. First Published October 13, 2017. doi.org/10.1177/1477153517734280.

paper When Hopkinson used his multiple criterion scale, test participants used adjustment to set the luminance representing a defined degree of discomfort. One limitation was that the four degrees of discomfort were evaluated only in ascending order.

In this experiment we repeated Hopkinson’s method but also using descending and randomised orders of discomfort. The different orders led to significant differences in luminance for a given degree of discomfort.

Kent MG, Fotios S, Altomonte S. Order effects when using Hopkinson’s multiple criterion scale of discomfort due to glare. Building & Environment 2018; 136: 54-61.

paper When evaluating discomfort the test participant must look somewhere, and for evaluating discomfort from peripheral sources a fixation task is used. This experiment compared the use of a simple fixation mark and a task requiring a degree of cognitive attention. The results confirmed a lower degree of discomfort is expressed when engaged in a task demanding a higher degree of cognitive attention.

Kent MG, Fotios S, Altomonte S. An experimental study on the effect of visual tasks on discomfort due to peripheral glare. Leukos. On-line first, 2018 DOI: 10.1080/15502724.2018.1489282.

paper Glare can impair vision (disability) as well as causing discomfort.

This article describes an experiment conducted to investigate how disability glare can affect target detection.

Winter J, Fotios S, Völker S. The effects of glare and inhomogeneous visual fields on contrast detection in the context of driving. Lighting Research and Technology. first published on October 7, 2016 as doi:10.1177/1477153516672719.

On-Going work
Further articles have been submitted which investigate the influence on discomfort evaluations of showing a pre-trial demonstration of the stimulus range, and of the bias induced by stimulus range itself.