Do colored overlays improve reading?: a test of the Irlen effect

The purpose of this study was to examine the use of colored overlays as an aid to individuals with reading problems; and, in particular, to assess the role visual contrast sensitivity may play in this treatment and in reading problems in general. Arguments both supporting and refuting the validity of the Irlen technique of using colored overlays and lenses as a treatment for reading problems are reviewed. While much of the criticism regarding the Irlen technique appears warranted, it seems that, for many reading disabled individuals, overlays and lenses do provide relief from symptoms and help to raise scores on reading tests. Tinted overlays may work by improving the contrast ratio of print for those with poorer contrast sensitivity. It was hypothesized that reading scores of many poor readers would improve with the addition of tinted overlays, that those who were helped would show poorer contrast sensitivity than those who were not, that contrast sensitivity would also improve with the addition of a tinted overlay, and that subjects would be equally helped bv a neutral density gray overlay.

One-hundred-seventy-four undergraduate volunteers were screened for reading ability with the Nelson Denny Reading Comprehension Test. The top 46 and bottom 46 were divided into three groups who were tested again using either a) one of four overlays deemed "optimal" for that subject by performance on the Tinker Speed of Reading test b) a gray overlay of the same density or c) no overlay. Contrast sensitivity was also tested under both conditions. The Irlen effect was not seen with this group of subjects. Results showed no significant effect of group or overlay color on reading performance. Scores in general increased significantly on the second trial, with low readers improving more than high readers. Contrast sensitivity showed no relationship to reading indices.