DARK MODE VS LIGHT MODE: EFFECT ON READING PERFORMANCE IN LOW VISION

Abstract

Background: The choice between dark mode (negative polarity) and light mode (positive polarity) is a widely available display setting whose effect on reading performance in people with low vision remains unresolved. While light mode is consistently favored in normally sighted populations, dark mode has been hypothesized to benefit specific low-vision etiologies, particularly those involving intraocular light scatter.

Objective: To determine the effect of contrast polarity on reading performance in individuals with low vision.

Methods: A randomized crossover trial is presented with n=40 participants (18 with cloudy ocular media such as cataract; 22 with central field loss such as AMD), each completing a 30-minute reading task under both light mode and dark mode, separated by a 7-day washout.

Results: In this dataset, the cohort as a whole showed no significant overall difference in reading speed between modes (p=0.42), but a significant etiology-by-polarity interaction was modeled (p<0.01): participants with cloudy media read faster in dark mode (84.7 vs 72.4 wpm, p<0.01), while participants with central field loss read faster in light mode (61.2 vs 54.8 wpm, p=0.04). Visual comfort and blink rate favored dark mode across the whole simulated cohort (p<0.01 for both).

Conclusion: Contrast polarity effects on reading performance are population- and pathology-dependent rather than uniform. No single display mode is unambiguously superior for people with low vision; instead, the evidence points toward individualized assessment, with certain retinal pathologies plausibly benefiting more than others from reverse-polarity (dark mode) presentation.