Previous studies of visually symptomatic dyslexics have found that their contrast thresholds for pattern discrimination are the same as non-dyslexics. However, when noise is added to the stimuli, contrast thresholds rise markedly in dyslexics compared with non-dyslexics. This result could be due to impaired noise exclusion in dyslexics. Some dyslexics report a reduction in discomfort experienced while reading and show increased reading speed when using coloured lenses. We hypothesised that coloured lenses work by aiding noise exclusion. Thus the coloured lenses should help performance best under conditions of high visual noise.
- visual noise
- vision sciences