The Glare Effect Test (GET): a tool to assess brightness or discomfort glare?

The Glare Effect is an illusion in which a white region appears self-luminous when surrounded by linearly decreasing luminance ramps (R). The Glare Effect Test (GET) was constructed as a paper test to easily measure luminosity thresholds within such illusion in different age groups with the following hypotheses: (i) GET can actually measure a perceptual process that changes along the lifespan; (ii) given that older adults present more symptoms of discomfort glare, they should show a lower threshold compared to young adults. Two groups of adults were recruited: young (20–30 years old) and senior (60–75 years old). Participants were assessed with GET and a battery of visual tests: acuity, contrast sensitivity, BHT, Ishihara, and the Navon effect. GET comprised 101 cards in which R changed gradually from solid black (card 0) to full black-to-white ramp (card 100). Subjects were required to classify cards on the basis of those two reference cards. PSEs show no correlation with the other visual tests, revealing a divergent validity. A significant difference between the groups ‘‘young’’ and ‘‘senior’’ was found: contrary to our expectations, luminosity thresholds for ‘‘senior’’ were higher than those for ‘‘young’’, suggesting a non linear relationship between luminosity perception and discomfort glare