HIGH LENS DENSITY AND IRIS PIGMENTATION ARE RELATED TO INDIVIDUAL DIFFERENCES IN GLARE DISCOMFORT

Authors

Etienne Choquart*, University of Georgia, Athens GA 30602Follow
Cameron J. Wysocky*, University of Georgia, Athens GA 30602Follow
Lisa M. Renzi-Hammond*, University of Georgia, Athens GA 30602Follow
Billy R. Hammond*, University of Georgia, Athens GA 30602
Jacob B. Harth, University of Georgia, Athens GA 30602Follow

Abstract

Glare discomfort (GD) is experienced during everyday visual tasks, such as driving at night or walking in brightly lit environments, and becomes more prevalent with age. It is important to understand what additional factors drive individual differences in GD to reduce adverse outcomes. To this end, we assessed whether iris color explains individual differences in GD in a sample of adults with optically dense lenses. GD and iris pigmentation were measured in 106 adults (40-67 years, M=49.81±7.13). GD was measured in two ways: through bioimaging of vertical differences in palpebral fissure size before and during light exposure and subjectively via a modified 5-point de Boer’s Scale. Iris lightness and hue were assessed through a standardized eye color chart. Lens optical density (LOD) was modeled using Pokorny’s model of lens transmission at 410nm. Wilcoxon rank-sum tests revealed no significant differences between dark and light irides in either palpebral fissure size (p=0.81) or subjective (p=0.61) GD. An ANCOVA demonstrated that iris hue significantly affected GD after controlling for lightness and LOD (F[4,100]=8.283,p<0.001 for palpebral fissure size; F[4,100]=3.127,p=0.02 for perceived discomfort). Tukey’s HSD post-hoc tests using estimated marginal means revealed significantly smaller palpebral fissure size in blue irides (M=2.88) than both hazel (M=6.86, p=0.01) and brown (M=6.60 p=0.003) irides. Tukey’s HSD post-hoc tests revealed significantly higher subjective GD in blue irides (M=3.19) than both hazel (M=4.40, p=0.008) and brown (M=4.06, p=0.03) irides. Older adults with blue irides may benefit more from strategies aimed at reducing exposure to glare such as polarized glasses for brightly lit environments and controlling gaze during nighttime driving. Accounting for iris pigmentation and the aging lens when treating GD will allow clinicians to improve assessment of and intervention for glare.

Acknowledgements

Lauren Hacker, OD

Recommended Citation

Choquart*, Etienne; Wysocky*, Cameron J.; Renzi-Hammond*, Lisa M.; Hammond*, Billy R.; and Harth, Jacob B. (2026) "HIGH LENS DENSITY AND IRIS PIGMENTATION ARE RELATED TO INDIVIDUAL DIFFERENCES IN GLARE DISCOMFORT," Georgia Journal of Science, Vol. 84, No. 1, Article 172.
Available at: https://digitalcommons.gaacademy.org/gjs/vol84/iss1/172