THE EFFECTS OF BLUE LIGHT-BLOCKING GLASSES VERSUS STANDARD LENSES ON CONTRAST SENSITIVITY AND VISUAL FATIGUE IN MYOPIC AND NON-MYOPIC ADULTS

Abstract

Background: Increased screen time has raised concerns about the effects of prolonged blue light exposure on visual health. Blue light, emitted by digital devices, has been linked to digital eye strain, visual fatigue, and potential retinal damage. With growing reliance on screens, the effectiveness of blue light-blocking glasses in alleviating these symptoms remains a subject of debate. This study evaluates the impact of blue light-blocking lenses on contrast sensitivity and visual fatigue in both myopic and non-myopic adults.

Objective: To assess the effects of blue light-blocking glasses on contrast sensitivity and visual fatigue in myopic and non-myopic individuals and determine their efficacy in reducing digital eye strain compared to standard lenses.

Methods: A double-blinded, randomized controlled trial was conducted with 64 participants, equally assigned to either blue light-blocking or standard lens groups. Participants underwent visual assessments at baseline, 2 weeks, and 4 weeks. Contrast sensitivity was measured using the Pelli-Robson chart, digital eye strain was evaluated using the Computer Vision Syndrome Questionnaire (CVS-Q), and visual fatigue was assessed using the Visual Fatigue Questionnaire (VFQ). Data were analyzed using Mann-Whitney U, Wilcoxon Signed-Rank, and Friedman tests.

Results: Contrast sensitivity in the blue light-blocking group improved significantly, increasing by 0.15 log units at 2 weeks (p = 0.03) and 0.12 log units at 4 weeks (p = 0.02). CVS-Q scores decreased by 5.6 points at 2 weeks (p = 0.04) and 8.3 points at 4 weeks (p = 0.01), indicating reduced digital eye strain. VFQ scores also showed a significant decline, with a 6.1-point reduction at 2 weeks (p = 0.03) and 5.8 points at 4 weeks (p = 0.02).

Conclusion: The findings suggest that blue light-blocking glasses significantly reduce visual fatigue and digital eye strain but do not enhance contrast sensitivity beyond standard lenses. Further studies with larger samples and longer follow-up periods are recommended to validate these results and guide clinical recommendations.