Flicker and reading speed: Effects on individuals with visual sensitivity.
Level 3 - non-randomized controlled study
Non-randomized experimental laboratory study by design analogy
PubMed 38711325 · doi:10.1177/03010066241252066
What was done
Across two laboratory experiments, researchers measured reading speed under different LED flicker conditions and text layouts. In Experiment 1, lights flickered at 60 Hz, 120 Hz, or 60 kHz (perceived as steady). In Experiment 2, lights flickered at 60 Hz, 600 Hz, or continuous light. Texts featured either high horizontal autocorrelation (striped) or low autocorrelation (less striped). Participants were categorized by visual sensitivity using the Pattern Glare (PG) Test.
What was found
Reading speed was slowest under 60 Hz and 600 Hz flicker and slower with high autocorrelation text. Participants in the low PG group exhibited greater flicker-induced reductions in reading speed than the high PG group, though the high PG group had slower baseline reading overall and was specifically slowed by high text autocorrelation. The abstract reports no numerical values, effect sizes, or test statistics.
Why it matters
This study demonstrates that both high-frequency flicker (including 600 Hz, where phantom arrays occur) and striped typography impair reading efficiency, particularly among visually sensitive individuals.
Limits
The abstract does not report sample size, participant demographics, exact reading speeds, or statistical test metrics. It remains unclear how these specific experimental lighting and text conditions generalize to typical real-world reading environments.
Cited by
- supports Invisible high-frequency light flicker from LEDs can cause eye strain, headaches, migraines, and anxiety.