The Long-Term Effect of Blue-Light Blocking Spectacle Lenses on Adults' Contrast Perception.

Purpose: To evaluate the long-term effect of two different degrees of blue-light blocking (BB) spectacle lenses on adults' contrast perception under various lighting conditions.

Methods: In total, 144 healthy adults aged 24.70 (±4.32 years) were recruited to this randomized controlled trial. The participants were randomly divided into three groups and used three different spectacle lenses (15% BB: 15% blue-blocking spectacle lenses; 30% BB: 30% blue-blocking spectacle lenses; RC: regular clear lenses serving as control). Contrast sensitivity under four light conditions (scotopic and photopic, both with/without glare) was measured using standard clinical tests at baseline, 1 month, 3 months and 6 months of use. The area under the log contrast sensitivity function (AULCSF) was also computed as an index for their overall contrast sensitivity across spatial frequencies.

Results: There was no significant difference in AULCSFs among the three types of spectacle lenses under any light condition (all > 0.81). No statistical difference was found in the AULSCF among the four time points (all > 0.39), with no interaction between the effects of group and time (all > 0.42).

Conclusion: Wearing blue-light blocking lens had no clinically significant effect on adults' long-term contrast perception under scotopic or photopic conditions, or with glare.