Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial

Abstract

To investigate if blue-blocking lenses are effective in reducing the ocular signs and symptoms of eye strain associated with computer use. Double-masked, randomized controlled trial. A total of 120 symptomatic computer users were randomly assigned (1:1) into a "positive" or "negative" advocacy arm (ie, a clinician either advocating or not advocating for the intervention via a prerecorded video). Participants were further sub-randomized (1:1) to receive either clear (placebo) or blue-blocking spectacles. All participants were led to believe they had received an active intervention. Participants performed a 2-hour computer task while wearing their assigned spectacle intervention. The prespecified primary outcome measures were the mean change (post- minus pre-computer task) in eye strain symptom score and critical flicker-fusion frequency (CFF, an objective measure of eye strain). The study also investigated whether clinician advocacy of the intervention (in a positive or negative light) modulated clinical outcomes. All participants completed the study. In the primary analysis, for CFF, no significant effect was found for advocacy type (positive or negative, p=.164) and spectacle intervention type (blue-blocking or clear lens, p=.304). Likewise, for eye strain symptom score, no differences were found for advocacy (p=.410) or spectacle lens types (p=.394). No adverse events were documented. Blue-blocking lenses did not alter signs or symptoms of eye strain with computer use relative to standard clear lenses. Clinician advocacy type had no bearing on clinical outcomes.