Impact of LED exposure on contrast sensitivity and protective efficacy of blue-blocking lenses

AIM: To measure the contrast sensitivity (CS) using computer-based Chart2020 software pre- and post-white light exposure with and without blue-blocking lenses (BBLs). METHODS: The study included participants aged 18 to 25y (n=30 eyes), where baseline CS was measured before the experiment. Following this, the participants were exposed to two white light-emitting diodes (LEDs; 450 lx each), placed at a 45-degree angle from the participant’s eye and 80 cm from the light source. All participants were randomly divided into three groups (BBL1- Placebo lens, BBL2- Crizal Prevencia, BBL3- Duravision) by sequential randomisation, which was double-blinded. Post-light exposure, the CS was measured monocularly with a calibrated computer-based CS Chart-2020 software at different log units. RESULTS: CS measured using Chart-2020 software at 0.8, 1.5, 6, 12, and 18 cpd pre- and post-white LED exposure with and without BBLs showed a significant difference (P<0.05) in contrast threshold and log contrast at 6 cpd and 18 cpd (P<0.05) and showed no significant differences in 0.8, 1.5, 12 cpd (P>0.05). CONCLUSION: This study shows that exposure to white LEDs can diminish CS, while BBLs may ameliorate these negative effects.