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

Am J Ophthalmol. 2021 Jun:226:243-251. doi: 10.1016/j.ajo.2021.02.010. Epub 2021 Feb 12.


Purpose: To investigate if blue-blocking lenses are effective in reducing the ocular signs and symptoms of eye strain associated with computer use.

Design: Double-masked, randomized controlled trial.

Methods: 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.

Results: 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.

Conclusions: 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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Asthenopia / diagnosis
  • Asthenopia / etiology
  • Asthenopia / prevention & control*
  • Color
  • Computer Systems*
  • Double-Blind Method
  • Eyeglasses*
  • Female
  • Filtration / instrumentation*
  • Humans
  • Male
  • Surveys and Questionnaires
  • Young Adult