New photochromic spectacle lenses improve glare discomfort and photostress recovery

To investigate the influence of a new photochromic spectacle lens on glare discomfort (GD) and photostress recovery time (PRT) in normal healthy subjects. A subject-masked within-subject comparison was performed using the fully activated state of Transitions® Gen S TM and clear control. 30 participants ( M = 19.2 ± 1.3 years) were tested. GD was assessed both physically, by measuring palpebral fissure size, and subjectively, via a 5-point Likert scale. PRT was measured as the amount of time necessary to regain visual function after an intense (∼15 % bleach) 5-second exposure to a broadband (emulated sunlight) light stressor. GD, measured both physically and subjectively was significantly reduced ( p < 0.001) when participants viewed the stimulus through the test lens compared to the clear control lens. PRT was also significantly reduced when using the test lens ( p < 0.001). These data are consistent with past findings but show that they apply to a commonly used photochromic tint. The results highlight the potential of specialized lenses to enhance visual comfort and performance in varying lighting conditions.