UNIVERSITY OF BIRMINGHAM The effectiveness and cost-effectiveness of coloured filters for reading disability: A systematic review Esther Albon, Yaser Adi & Chris Hyde Department of Public Health and Epidemiology West Midlands Health Technology Assessment Group DPHE 2008, Report Number 67 The effectiveness and cost-effectiveness of coloured filters for reading disability: A systematic review A WEST MIDLANDS HEALTH TECHNOLOGY ASSESSMENT COLLABORATION REPORT Report commissioned by: Regional Evaluation Panel Produced by: West Midlands Health Technology Assessment Collaboration Department of Public Health and Epidemiology The University of Birmingham Authors: Esther Albon, Systematic Reviewer Yaser Adi, Systematic Reviewer Chris Hyde, Director of WMHTAC Correspondence to: Dr Esther Albon Department of Public Health and Epidemiology The University of Birmingham Edgbaston Birmingham B15 2TT Date completed: January 2008 Expiry Date: January 2011 Report Number: 67 ISBN No: 0704426951 9780704426955 © Copyright, West Midlands Health Technology Assessment Collaboration Department of Public Health and Epidemiology The University of Birmingham 2008 Coloured filters for reading disability WEST MIDLANDS HEALTH TECHNOLOGY ASSESSMENT COLLABORATION (WMHTAC) The West Midlands Health Technology Assessment Collaboration (WMHTAC) produce rapid systematic reviews about the effectiveness of healthcare interventions and technologies, in response to requests from West Midlands Health Authorities or the HTA program. Reviews usually take 3-6 months and aim to give a timely and accurate analysis of the quality, strength and direction of the available evidence, generating an economic analysis (where possible a cost-utility analysis) of the intervention. CONTRIBUTIONS OF AUTHORS: Esther Albon (re)designed the protocol, identified included studies, undertook data extraction and quality assessment, identified included studies for the cost effectiveness section, and wrote the report. Yaser Adi designed the first draft of the protocol, and undertook study identification at the title and abstract stage. Chris Hyde advised on the protocol, wrote the section on cost effectiveness and advised on the general writing of the report. CONFLICTS OF INTEREST: None ACKNOWLEDGEMENTS: The authors would like to thank those in the Department of Public Health and Epidemiology, University of Birmingham: Jayne Wilson for advice on study designs, outcome assessment and commenting on the draft report; Sue Bayliss for her assistance in designing and conducting the electronic literature searches; Natalie Rowles, Linda Briscoe and Ann Massey for administrative assistance; Bernie Lee for checking the data of included RCTs; Martin Connock for help with the meta-analysis. The authors also wish to thank Dr Frank Eperjesi, School of Life and Health Sciences, Aston University for commenting on the draft report and providing information on costs and relevant articles . 2 Coloured filters for reading disability West Midlands Regional Evaluation Panel Recommendation Not proven and not supported. Given the potential size of the problem there is a need for more basic research in this area Anticipated expiry date: January 2011 3 Coloured filters for reading disability GLOSSARY/ABBREVIATIONS AND ACRONYMS Abbreviatio Definition n/ Acronym ARIF Aggressive Research Intelligence Facility CI confidence interval FRI Formal Reading Inventory ICER incremental cost effectiveness ratio IDPS Irlen Differential Perceptual Schedule ITT intention to treat LEA Local Education Authority m month MRC Medical Research Council MIS Meares-Irlen Syndrome Neale Neale Analysis of Reading Ability NLS National Literacy Strategy (primary) NR not reported pb placebo PCT primary care trust QoL quality of life RCT randomised controlled trial RD reading disability REP Regional Evaluation Panel SD standard deviation SE standard error SEN special educational needs SLD specific learning difficulties SMD standardised mean difference SRD specific reading difficulties SSS scotopic sensitivity syndrome tx treatment Viss “Vision” software WMHTAC West Midlands Health Technology Assessment Collaboration WRRT Wilkins Rate of Reading Test y year Note on terminology: Please note that RD is used throughout the review for simplicity but some articles may have used different terminology such as dyslexia, specific reading difficulty, specific learning difficulty, developmental reading disorder, reading difficulty, reading problem, specific learning disability and specific reading disorder. These terms all refer to a reading deficit without an obvious cause. 4 Coloured filters for reading disability EXECUTIVE SUMMARY Background Reading disability affects up to 18% of school-aged children in the UK. If left untreated it can adversely affect emotional, behavioural and socio-economic outcomes in adulthood. It has been hypothesised that coloured filters fitted as either glasses or contact lenses, or used as an overlay, may improve reading ability. Aim To use the process of systematic review to assess the effectiveness, and cost effectiveness, of coloured filters for reading disability. Methods Databases (MEDLINE, EMBASE, CINAHL, PsychINFO, Science Citation Index and the Cochrane Library) were searched from the database start date to September 2007 using appropriate terms and filters. Randomised controlled trials, quasi- randomised controlled trials and non-randomised controlled trials employing the relevant intervention (tinted or coloured lenses, glasses, or overlays) and comparator (no treatment, placebo or other current treatment) in subjects with reading disability were included. Subjects had to be aged 7 years or over. Studies were only included if outcomes of reading accuracy, speed and comprehension, or the symptoms, behaviour or quality of life associated with reading disability were assessed. Study inclusion, data abstraction and quality assessment were performed before quantitative and qualitative data analyses were carried out. A systematic review of costs, and cost-effectiveness studies for the use of coloured filters for reading disability was conducted. Searches were undertaken during September to December 2007 using ERIC and OHE HEED in addition to the databases listed above. Any study relevant to the review question was included. It was not possible to develop an economic model to address the cost-effectiveness of coloured filters for reading disability. 5 Coloured filters for reading disability Results One quasi-systematic review was identified by the searches. Eight RCTs (four parallel studies and four crossover studies) were included in the review of effectiveness of coloured filters for reading disability. A number of different tests and scales were used to assess reading across the 8 studies. Study quality was generally poor. Threats to the validity of the results included small sample sizes, inadequate controls, lack of reporting of randomisation methods, difficulty in the maintenance of any blinding, and high levels of attrition. A further design flaw was identified in five studies, which used the intervention under evaluation to screen and enrol subjects showing some benefit with the intervention, prior to being randomised into the intervention or comparator groups (selection bias). Meta-analysis for the outcome of reading accuracy (3 studies) showed no clear benefit to using coloured filters for reading accuracy compared to using the control. The two studies that could not be incorporated into meta-analysis reported a statistically significant improvement and no statistically significant improvement with preferred coloured filters compared to the control. Meta-analysis of reading speed and reading comprehension data (4 studies for each outcome) showed no clear benefit to using coloured filters for reading speed or comprehension compared to using the control. The two studies that could not be incorporated into meta-analysis for either outcome reported a statistically significant improvement and no statistically significant improvement with preferred coloured filters compared to the control. The results of the meta-analysis should be treated with caution since the trial design, patient characteristics and outcome tests varied considerably between studies. Based on the I 2 statistic, however, statistical heterogeneity between studies was low. Two studies evaluated the outcome of symptoms of visual stress that can be associated with reading disability. Both studies used subjective measures to show that there was a statistically significant improvement in the level of symptoms when coloured filters were used compared to the control. The long-term effects of using coloured filters were not evaluated as part of the randomised design by any of the included RCTs. None of the studies reported 6 Coloured filters for reading disability behaviour, quality of life or adverse effects of using coloured filters for reading disability. A further 15 non-randomised comparative studies were also identified that matched the review inclusion criteria. Methodological quality was very poor, with many threats to study validity. A pre-existing economic evaluation of the use of coloured filters for reading disability was not identified by the searches. Only limited cost data on coloured filters and reading disability was available. In addition, there was little information on the long- term impact of reading disability. It was therefore not possible to provide an estimate of cost-effectiveness of coloured filters for reading disability. Conclusions