Improving filter recommendations: the role of individual light sensitivity in ecological conditions

This study investigates the optimal transmittance settings for discomfort glare filters under ecological outdoor conditions, accounting for individual light sensitivity and varying light conditions. The objective is to guide the personalization of sunglass transmittance to enhance visual comfort in various outdoor environments.

Twenty-eight participants (18 women and 10 men, aged 18-61) were equipped with electrochromic glasses with a visible light transmittance ranging from 80% to 5%. For each participant, preferred transmittance was assessed in three light conditions (facing the sun, back to the sun, and in the shade) using three methods (clearest-to-dark, darkest-to-clear, and manual settings). Individual light sensitivity was quantified using the Eye Resistance Score (ERS) measured by the Lumiz 100™ device. A logistic model was designed to predict the optimal transmittance settings.

A total of 1,530 transmittance settings were recorded. Illuminance, method, and light sensitivity (ERS) all significantly contributed to the model predicting optimal transmittance. Less sensitive participants required category 2 filters (43-18% transmittance) for high illuminations, while more sensitive participants needed category 4 filters (8-3% transmittance) under equivalent light conditions for direct sunlight.

Personalized filter recommendations based on individual light sensitivity and outdoor conditions can enhance visual comfort. This study highlights the importance of considering individual variability in light sensitivity to optimize discomfort glare protection. Further research in diverse environments and lighting conditions could help refine these recommendations.