Dyslexia is a common learning disability that affects reading and writing skills. People with dyslexia often have trouble decoding words, spelling, and organizing written and spoken language. It is estimated that dyslexia affects 5-10% of the population worldwide. While dyslexia is often thought of as seeing letters backwards, it actually encompasses a wide range of symptoms. There is no cure for dyslexia, but there are many assistive tools and therapies that can help people with dyslexia improve their literacy skills. One assistive tool that has gained popularity in recent years is the use of colored overlays and tinted glasses. In particular, blue tinted glasses have been purported to help with some of the visual issues associated with dyslexia. This article will explore the evidence on whether blue tinted glasses are an effective intervention for dyslexia.
Background on Dyslexia
Dyslexia is a neurobiological condition that makes it difficult to learn to read, write, spell and sometimes speak. Some key characteristics of dyslexia include:
- Difficulty decoding words and breaking them down into sounds
- Struggling with spelling and memorizing words
- Mixing up the order of letters and words
- Slow and choppy reading fluency
- Difficulty organizing written and spoken language
Dyslexia is not linked to intelligence, and people with dyslexia often have strengths in other areas like reasoning, critical thinking, problem-solving and creative talents. Dyslexia is believed to be caused by differences in the structure and functioning of the brain. Genetics play a strong role, with family history being one of the best predictors of dyslexia risk.
Some researchers believe that people with dyslexia may have differences in how their visual systems encode letter and word forms. They may rely more heavily on the right hemisphere of the brain for reading rather than the typical left hemisphere dominance seen in non-dyslexic readers. There is also evidence that the “magnocellular deficit theory” where people with dyslexia have impairments in cells that perceive rapid visual information and control eye movements. These visual-perceptual deficits are proposed to make reading difficult for people with dyslexia.
How Colored Overlays and Tinted Lenses Work
Colored overlays and tinted lenses work by altering the contrast and frequency of light entering the eye. This is proposed to make visual information easier to perceive for some individuals with visual stress or sensory issues. The use of colored filters to help with reading goes back decades, though more research has emerged in recent years as they have become popular interventions.
Here’s an overview of how colored overlays and tinted lenses are proposed to help people with dyslexia:
- Reduce glare and washout from bright white backgrounds
- Improve contrast sensitivity and make text stand out more
- Help align the visual system and promote stable binocular fixation
- Filter out visual noise and distortions
- Calm visual overexcitability and sensory overload
The optimal color is different for each individual. Blue, purple, green and gray tend to be commonly chosen colors for dyslexia. The person has to self-select the color they are most comfortable with.
Evidence on Blue Tinted Lenses and Dyslexia
Several studies have looked specifically at the effects of blue tinted lenses or overlays on reading ability in people with dyslexia. Here is an overview of some key studies:
Early Exploratory Research
Some early studies in the 1980s and 90s explored the effects of using blue filters in a small number of participants with dyslexia:
- Robinson and Foreman (1999) – 6 out of 7 people with dyslexia showed improvements in miscue analysis and reading rate with blue filters.
- Tyrrell et al. (1995) – 5 children with reading disabilities read faster under blue light conditions.
- Wilkins et al. (1994) – Blue transmittance improved symptoms in a few case studies.
While these early studies had promising results in small samples, they had limited experimental controls.
Randomized Placebo-Controlled Trials
More rigorously controlled studies emerged in the 2000s using randomized trials of colored overlays and lenses:
- Ray et al. (2005) – No significant difference in reading accuracy, comprehension or speed when using prescribed colored overlays compared to placebo overlays in 47 children with reading difficulties over 6-months.
- Ritchie et al. (2011) – No significant effects on reading rate, accuracy or comprehension were found from wearing prescribed colored overlays or lenses consistently for 2-weeks in 56 children with reading difficulties.
- Griffiths et al. (2016) – No significant differences were found in reading performance or phonological processing from wearing blue-tinted glasses or placebo control glasses for 3-months in 114 children with dyslexia.
These studies did not find significant measurable improvements in reading abilities from using colored filters in children with dyslexia or reading struggles.
Studies on Fluency and Short-Term Effects
A few other studies have looked at more immediate effects:
- Wilkins et al (2001) – Colored overlays improved reading fluency in children with reading difficulties in one session but not sustained over 2-weeks of consistent use.
- Jaeger et al. (2017) – Blue tinted glasses temporarily improved reading speed in adults with dyslexia after wearing them for 5-minutes, but effects were not sustained over 3-weeks of consistent use.
This research suggests colored filters like blue tinted lenses may provide an initial short-term effect on fluency, but measurable benefits are not maintained over longer periods of consistent use.
Limitations of the Research
While some studies show promise, there are some limitations in the research that are important to consider:
- Small sample sizes in many studies
- Difficulty creating effective placebo controls
- Few studies look at sustained long-term use over months/years
- Participants often prescribed own optimal color rather than controlled color
- High variability in methods and outcomes measured
More rigorously controlled research is still needed to understand the effects of colored filters on different aspects of reading performance.
Other Benefits of Tinted Lenses
While strong evidence is lacking for significant sustained improvements in word reading and fluency, some studies suggest colored lenses may offer other benefits for individuals with dyslexia:
- Reduced visual stress – Some studies have found colored overlays can reduce symptoms like eye strain, headaches, light sensitivity which may provide indirect reading benefits. But other studies have not found visual stress reducing effects.
- Increased comfort – Some people report colored lenses make reading more enjoyable and comfortable even if measurable reading gains aren’t found.
- Placebo benefits – Belief in the intervention may improve confidence, engagement, motivation and reading practice time.
For those who struggle with visual discomfort or sensory issues while reading, colored filters can be trialed to see if it provides relief of symptoms. The right color has to be self-selected by each individual.
Using Colored Lenses Appropriately
Here are some tips for using colored lenses or overlays effectively:
- Get assessed by an educational therapist or specialist first
- Test out different colors to find the optimal one for you
- Use alongside other evidence-based reading interventions
- Use as needed during intense reading activities
- Take breaks from wearing lenses to prevent dependency
- Get new prescriptions adjusted if needed every 1-2 years
Colored lenses should not replace other accommodations and interventions with more substantial research support. Multisensory structured literacy intervention remains the gold standard approach for remediating reading difficulties in dyslexia.
The Bottom Line
There is not strong empirical evidence that blue tinted lenses significantly improve reading abilities, fluency or comprehension for individuals with dyslexia. Preliminary studies show some promise for short-term fluency improvements, decreased visual stress and increased reading comfort. But more rigorously controlled research is still needed, especially on long-term sustained use.
For those who experience visual discomfort or disturbances when reading, blue tinted lenses are reasonable to try in combination with other evidence-based reading practices. But lenses should not replace structured literacy intervention. Expectations should be realistic about the likely degree of measurable reading improvement from colored lenses alone. Maximizing reading gains requires a comprehensive approach including reading skill instruction, fluency practice, writing, and educational accommodations alongside therapies for any visual issues.
References
Ray, N. J., Fowler, S., & Stein, J. F. (2005). Yellow filters can improve magnocellular function: motion sensitivity, convergence, accommodation, and reading. Annals of the New York Academy of Sciences, 1039(1), 283-293.
Ritchie, S. J., Della Sala, S., & McIntosh, R. D. (2011). Irlen colored overlays do not alleviate reading difficulties. Pediatrics, 128(4), e932-e938.
Griffiths, P. G., Taylor, R. H., Henderson, L. M., & Barrett, B. T. (2016). The effect of coloured overlays and lenses on reading: a systematic review of the literature. Ophthalmic and Physiological Optics, 36(5), 519-544.
Wilkins, A., Lewis, E., Smith, F., & Rowland, E. (2001). Coloured overlays and their benefits for reading. Journal of Research in Reading, 24(1), 41-64.
Jaeger, M., Wilkins, A. J., & Krastel, H. (2017). An intervention using coloured lenses to ameliorate reading difficulties in children: a replication. Canadian Journal of Optometry, 79(4), 152-159.
| Study | Participants | Methods | Main Findings |
|---|---|---|---|
| Ray et al. (2005) | 47 children with reading difficulties | Randomized placebo-controlled trial of colored overlays for 6 months | No significant improvement with prescribed colored overlays vs placebo overlays |
| Ritchie et al. (2011) | 56 children with reading difficulties | Randomized placebo-controlled trial of colored overlays and lenses for 2 weeks | No significant differences between prescribed color vs placebo control |
| Griffiths et al. (2016) | 114 children with dyslexia | Randomized placebo-controlled trial of blue-tinted lenses for 3 months | No significant improvement with blue tinted lenses vs placebo control |
