The expense of such treatment is unwarranted and may divert resources from evidence-based treatment. Critics claim that the symptoms of those with Scotopic Sensitivity Syndrome are related to already known visual perceptual and neurological disorders. According to a statement released by the American Optometric Association in 2004:
There is evidence that the underlying symptoms associated with specifically Meares Irlen Syndrome, are related to identifiable vision anomalies, e.g., accommodative, binocular, and ocular motor dysfunctions, in many patients seeking help from coloured lenses. Furthermore, such conditions return to normal function when appropriately treated with lenses, prisms, or vision therapy. When patients exhibiting Meares Irlen Syndrome were treated with vision therapy, their symptoms were relieved. These patients were no longer classified as exhibiting this syndrome, and therefore did not demonstrate a need for the coloured overlays or tinted lenses. As outlined by Hyatt, Stephenson and Carter (2009):
In 1990, the Journal of Learning Disabilities published a special issue that provided intensive coverage of Irlen lenses. In the preface to the issue, the editor in chief, Wiederholt, noted that each of the studies had serious theoretical, medical/physical, and methodological flaws, but were published along with articles critiquing the studies to provide readers with an overview of the Irlen procedures as well as guidance for conducting quality research studies. He, along with Hoyt (1990), Parker (1990), and Solan (1990), noted that these initial studies by Blaskey et al. (1990), OConnor, Sofo, Kendall, and Olsen (1990), and Robinson and Conway (1990) failed to support the treatment validity of colored overlays.
Irlen syndrome was also studied in Australia by Greg Robinson (1944–2008) at the University of Newcastle. He was director of the Special Education Centre at the School of Education.In the US, peer-reviewed literature on the topic suggests that much is unknown about the cause of these disorders, ranging from the 2011 study in a journal of the American Academy of Pediatrics, "Irlen Colored Overlays Do not Alleviate Reading Difficulties" and the 2012 study in the journal Brain Topography, "A Functional Neuroimaging Case Study of Meares–Irlen Syndrome". The first, purely in relation to Meares-Irlen syndrome, finds that there is no evidence for one of the fundamental claims of therapeutic benefit. The second, which focused primarily on Irlen syndrome, found compelling evidence of unique brain function linked to the syndrome. Treatment
The College of Optometrists (UK) has specified guidelines for optometrists who use the colorimeter system. A society for coloured lens prescribers has been established to provide a list of eye-care practitioners with expertise in the provision of coloured lenses for the treatment of visual stress. Irlen Method
The Irlen Method uses coloured overlays and tinted lenses in the form of glass or contact lenses. The method is intended to reduce or eliminate perceptual processing errors; it is claimed the resultant retiming of visual signals in the brain improves the reading difficulties associated with scotopic sensitivity syndrome.