Individuals with dyslexia use a different visual sampling strategy to read text

This study aimed to develop a comprehensive profile of eye movements in adults with dyslexia during naturalistic, silent paragraph reading. While reading speed deficits in dyslexia are well-documented, the specific visual sampling strategies—how readers move their eyes to encode text—remain less understood. The researchers compared 35 adults with dyslexia to 32 matched controls, using standardized International Reading Speed Texts (IReST) presented in two different fonts (Times New Roman and OpenDyslexic) to ensure ecological validity. They analyzed both traditional metrics (fixation duration, saccade amplitude, regressions) and contemporary metrics (line-initial fixation duration, scanpath similarity, and atypical directional deviations) to determine if dyslexic readers employ a fundamentally different strategy for processing written information.

The study confirmed that adults with dyslexia read significantly slower than their non-dyslexic counterparts. Eye-tracking data revealed a consistent, more laborious visual sampling strategy: dyslexic readers exhibited longer fixation durations, shorter saccade amplitudes, and fewer skipped words. Notably, they also showed longer line-initial fixation durations, which the authors interpret as evidence of slower lexical access, as these fixations lack the benefit of parafoveal preview. Furthermore, the researchers identified a higher frequency of atypical eye movements—termed directional deviations—where the eyes moved in directions unexpected for normal reading, suggesting occasional oculomotor control issues. Computational analysis of scanpaths confirmed that even when controlling for reading duration, dyslexic readers sample identical texts using a different sequence of fixations than non-dyslexic readers.

These findings provide a detailed, multi-layered account of how dyslexia manifests in the oculomotor behavior of adults. By demonstrating that dyslexic readers do not simply read slower but actually sample text differently, the study supports the theory that reading struggles in dyslexia are rooted in an interplay between inefficient linguistic processing (specifically lexical access) and potential oculomotor deficiencies. This comprehensive profile helps clarify the debate regarding the aetiology of dyslexia, suggesting that while phonological and lexical processing deficits are primary, oculomotor factors also play a measurable role in the reading experience.