Discomfort glare from daylight: Influence of transmitted color and the eye's macular pigment

Designing architectural façades that allow sufficient daylight to create visually comfortable and pleasantenvironments is a challenging aspect of building design. It requires accounting for visual comfort anddiscomfort glare risks and understanding the factors that influence them. In the last two decades, severalprediction models have been developed to quantify discomfort glare by considering almost exclusivelythe photometric properties and spatial distribution of incoming light. Although these empirical modelshave been derived to best match one's perception of glare, they fail to account for the significant interindividualvariability that exists in glare perception and are furthermore limited in their applicability incertain visual environments. It is evident from the literature that not all the factors influencingdiscomfort glare perception are known and accounted for in the existing prediction models. Based onthe literature review, we have identified two potential factors, namely, the macular pigment density inthe retina and the color of daylight, as likely to influence discomfort glare perception. Up to now, theirinfluence on glare induced by daylight has remained unknown.To address this gap, this thesis aims to determine the influence of macular pigment density and color ofthe sun disc (altered by colored glazing) on discomfort glare perception in daylit environments. Bymeans of three psychophysical experiments conducted in office-like test rooms along with the ocularexaminations of the participants, we determined the influence of macular pigment and color of daylighton the perception of discomfort glare for young and healthy individuals. Three experiments wereconducted, one with blue electrochromic glazing, one with color-neutral glazing, and the third with red,blue, green, and color-neutral glazing. Each experiment followed a similar protocol of exposing everyparticipant to four daylight glare scenarios and recording their responses to questionnaires. The fourdaylight scenarios differed either in color or in the transmittance of the glazing through which the sunwas visible as the primary glare source. The remaining windows were set in a way to keep the overallcolor rendering in the space as neutral as possible.The results show that macular pigment density does not influence discomfort glare perception from thesun disc filtered by color-neutral glazing in the near-peripheral field of view. However, when exposedto the sun disc filtered by saturated blue-colored glazing also in the near-peripheral field, participantswith higher macular pigment density were better able to tolerate the glare, indicating a significantinfluence of macular pigment in this case.In regards to the influence of color, results show that the perceived color of the sun disc (as filtered bycolored glazing) has a strong influence on participants' perception of glare. Direct sunlight filteredthrough four types of colored glazing of a similar visible (photopic) transmittance caused significantlydifferent levels of discomfort glare perception amongst the participants. More precisely, participantsexperienced statistically higher levels of glare under the red and blue glazing compared to the colorneutralor green glazing.The findings show that the photopic luminosity function (V2°(l)) is not an appropriate weightingfunction to characterize the spectral sensitivity of the human eye when a high-intensity colored glaresource is in