Dyslexia is a common learning disability that affects reading, writing, and spelling skills. Some estimates suggest dyslexia impacts between 5-20% of the population. While dyslexia is often thought of as seeing letters backwards, it actually encompasses a wide range of symptoms. Individuals with dyslexia may struggle with phonological processing, processing speed, short-term memory, auditory processing, visual processing, and other skills related to learning language-based tasks. This complex condition makes reading, writing, and spelling more difficult for affected individuals.
There is no cure for dyslexia, but various assistive tools and therapies can help dyslexic students better manage their symptoms. In recent years, colored overlays and tinted lenses have gained popularity as a tool to help with visual processing challenges associated with dyslexia. But do these actually help? Let’s explore what the research says.
What are colored overlays?
Colored overlays are sheets of transparent colored plastic that can be placed over text. The overlay creates a color tint over the text that is thought to improve visibility, reduce glare, and ease eyestrain for some readers with visual processing differences. The most commonly used colors are rose, azure, green, yellow, and purple. Colored overlays can be used with books, worksheets, computers screens, tablets, and other surfaces.
What does the research say about colored overlays for dyslexia?
There have been several studies investigating the effectiveness of colored overlays for individuals with dyslexia and other reading disorders. Here is a summary of some key findings:
| Study | Findings |
|---|---|
| Wilkins et al. (1994) | In a study of 114 children with reading difficulties, around 80% improved reading speed and accuracy with an optimal colored overlay. |
| Robinson and Foreman (1999) | In a study of 20 dyslexic and 47 normal readers aged 7-11, colored overlays improved reading speed for 37% of dyslexics compared to 13% of normal readers. |
| Kriss and Evans (2005) | A study of 322 school children found 35% improved reading speed with colored overlays. Children with reading difficulties were more likely to benefit. |
| Henderson et al. (2013) | No significant difference in reading rate for dyslexic children using preferred colored overlay versus clear overlay in a robust study of 116 children. |
While some studies have found benefits for a subset of readers, others have not found a significant effect. A major limitation across studies is the placebo effect – children may read better simply because they expect the overlay to help. More rigorously controlled studies are needed to determine true impacts.
Potential benefits of colored overlays
Although the evidence is mixed, some studies and anecdotal reports suggest colored overlays may offer the following benefits for some dyslexic readers:
- Increased reading speed and accuracy
- Improved visibility and comfort
- Reduced eye strain and fatigue
- Minimized glare and harsh contrasts
- Greater concentration and focus
- Decreased visual stress and distractions
These effects can make reading less tiring and fluent reading more achievable for those with visual processing challenges. The right overlay color can improve perception of text, which may allow struggling readers to better focus on decoding and comprehension.
How are optimal colors for overlays determined?
If colored overlays are to be tried, it is important to identify the optimal overlay color for each individual. This can be determined through testing by specialists such as educational psychologists, optometrists, and dyslexia tutors. The process involves testing different colored overlays while the individual reads text passages aloud. The overlay color that yields the fastest reading speed and fewest errors is considered optimal.
Alternatively, some standardized assessments include a colored overlay component. Examples include the Irlen Screening Assessment and the Intuitive Overlays Assessment. These step-by-step assessments systematically compare reading performance across a range of overlay colors to identify the best color for each person.
Recommendations for use
Here are some tips to maximize the potential benefits of colored overlays:
- Get tested to identify the optimal color – don’t just choose one subjectively
- Use the recommended color consistently across reading tasks
- Ensure proper overlay size to fit the reading material
- Experiment to find the optimal overlay opacity – some benefit from more transparent tints
- Use overlays for reading, not all day – constant color can cause dependence
- Combine with other evidence-based interventions and accommodations
While colored overlays show promise for some, they should not replace proven reading interventions. Multisensory, structured literacy programs have stronger evidence for improving reading skills in dyslexia. Overlays may provide additional visual support when used alongside these comprehensive interventions and accommodations.
What about tinted lenses?
Tinted lenses work on a similar principle to overlays but have the color tint embedded into the lens material rather than overlaying the text surface. Tinted glasses must be carefully customized using prescribed colors and densities based on assessment results. As with overlays, some studies show benefits such as improved reading performance for subsets of dyslexic individuals. However, more rigorous controlled research is still needed, as placebo effects may inflate some findings. Tinted lenses may be an option for those who struggle with visual stress from screens and environmental stimuli, in addition to reading. But overlays tend to provide more flexibility since they can be used selectively for reading tasks.
Downsides and limitations
While colored overlays show promise, it’s important to understand their downsides and limitations:
- Lack of rigorous research and mixed findings on efficacy
- Expense of customized overlays and screening assessments
- Time and effort required for specialized evaluation
- Potential dependence on overlays long-term
- Not a cure – does not teach decoding or comprehension skills
- Can slow processing if overlay color is not optimal
- Difficult to use with some materials (computer screens, tablets, phones)
- Insufficient on their own for severely dyslexic readers
For these reasons, overlays may be most suitable as an additional support rather than the primary intervention when addressing dyslexia.
Conclusion
Research on colored overlays for dyslexia has produced mixed results. Some studies show faster reading speeds and reduced errors for a subset of dyslexic individuals when using an optimal overlay color. For those who are visually sensitive, overlays may improve text visibility and comfort. However, placebo effects may inflate some findings, and benefits do not appear universal. Overlays should be considered an adjunct rather than a substitute for evidence-based reading interventions when addressing dyslexia. Controlled trials are still needed to clarify how effective overlays are for different groups. But they may provide supplemental visual support when used selectively alongside proven dyslexia therapies.
