Coloured or Irlen lenses for reading difficulties

The question here is one primarily about treatment and you want to find an evidence-based answer to provide to the child's mother and to inform your intervention.

The suggested PICO question here is: For children with reading difficulties (P) does coloured lenses (I) improve vision and/or reading ability (0).

The PICO has been put into the table below to determine keywords and synonyms that will facilitate the next step - acquiring secondary and primary sources of external evidence.

[The OR and AND operators help specify the search and the asterix (*) is a truncation/ wildcard symbol allowing for any word ending to be found. For example, child* covers child and children. For more information see the resource How to use a PICO to search effectively]

To find out more about using this PICO table or to find a worksheet to use for your own questions, click here.
 

Searching using the PICO:

The suggested PICO from Step 1: Ask was For children with reading difficulties (P) does coloured lenses (I) improve vision and/or reading ability (0). Using the PICO table keywords and synonyms were established, developing a search string of:

(Child*) AND (reading or learning or comprehension) AND (colour* or color* or Irlen) AND (len* or overlay) AND (vision). To see this as a worked example, please click here. This string can now be used to specifically search in a range of different search databases.

Learning activity 1: cut and paste the above string (in italics) in Google Scholar (https://scholar.google.com)

-  how relevant the articles are to the question
- use the options on the left to further specify your search (e.g. by setting a year limit)
- determine if the resources are primary sources (studies) or secondary sources (syntheses or reviews)

Time effective searching?

Secondary resources - summaries and syntheses of studies that already exist - are a good starting place to see if someone else has already completed a review of this literature. Such resources still require appraisal (in Step 3) but save time as you don't have to read and appraise every individual study on the topic. 

Learning activity 2: A list of secondary sources that may be relevant can be found on this site by clicking here. Have a go at finding secondary sources using these sites and compare them to the documents found under the "Treatment" tab below.

Treatment

The table below shows the secondary sources found from the following websites. If you have found other secondary sources, feel free to email us and let us know.

The clinical practice guidelines and secondary sources found require appraisal to determine how believable the conclusions are.

However developed and published appraisal tools are lacking for secondary sources, unlike primary sources.

The National Health and Medical Research Council clinical practice guideline portal reports 4 criteria for which practice guidelines, policy statements and other summaries can be appraised:

1. The clinical practice guideline contains statements that include recommendations, strategies, or information that assists health care practitioners and patients make decisions about appropriate health care for specific clinical circumstances.The NHMRC does not (except in the case of NHMRC approved guidelines) evaluate the accuracy of the reasoning contained in or the conclusions reached by the guideline.
2. The clinical practice guideline was produced under the auspices of medical specialty associations; relevant professional societies, public or private health organisations, non-government agencies or government agencies at the federal or state level for current use within Australia. A clinical practice guideline developed and issued by an individual not officially sponsored or supported by one of the above types of organisations does not meet the inclusion criteria.
3. Corroborating documentation can be produced that a systematic literature search and review of existing scientific evidence published in peer reviewed journals was performed during the guideline development. A guideline is not excluded if corroborating documentation can be produced detailing specific gaps in scientific evidence for some of the guideline's recommendations.
   The NHMRC confirms that a systematic literature search was conducted by the Guideline developer, however the NHMRC has not (except in the case of NHMRC approved guidelines):
   
   - evaluated the accuracy of the information contained in the guidelines;
   - evaluated the accuracy of the information contained in the corroborating documentation; or
   - evaluated whether the corroborating documentation cited by the guideline in fact supports the statements or recommendations contained within the guideline.
   
   
4. The full text guideline is available upon request in print or electronic format, in the English language. The guideline is current and the most recent version produced. Documented evidence can be produced or verified that the guideline was developed, reviewed, or revised within the last five years.
    

This is just one example of how such sources could be appraised.
 

Treatment

As an example, the American Academy of Pediatrics (2011) published guideline will be appraised:
 

Overall the Joint Statement met the majority of the criteria - it is recent, is produced by reputed organisations and is available on the internet. The main issue is that a systematic search for the literature was not reported. Inclusion and exclusion of studies was also not reported. Even though in-text referencing is used to suport claims, it is unclear whether all the possible studies on the topic were included in the review or if there was any bias in searching, selecting or referencing studies in the statement.

The Joint Statement concluded that:

"Visual problems do not cause dyslexia. Scientific evidence does not support the efficacy of eye exercises, behavioral/perceptual vision therapy, training glasses, or special tinted filters or lenses in improving the long-term educational performance in these complex pediatric neurocognitive conditions. Recommendations for multidisciplinary evaluation and management must be based on evidence of proven effectiveness demonstrated by objective scientific methodology.^{106,112,239,270,276} It is important that any therapy for learning disabilities be scientifically established to be valid before it can be recommended for treatment.¹⁰⁶ Because vision therapy is not evidence based, it cannot be advocated." (page e849, column 2, paragraph 2)

The diagram attached discusses the factors and conclusion of application for Irlen lenses to the original clinical case.