Visual stress in the classroom: a review of fluorescent lighting, ultra-white paper, reading discomfort and unexplained learning difficulties

Abstract

A key stimulus behind the present review has been the growing debate among educational researchers, politicians and the general public concerning apparent declines in the literacy and numeracy levels of school students in developed nations. The last two decades have born witness to a plethora of studies that have primarily focused upon reading and writing deficits in children with familiar learning disorders, such as developmental dyslexia and/or attention deficit/hyperactivity disorder (ADHD), while other studies have investigated the respective incidences of these well-publicised disorders. At the same time however, the very common visual processing disorder Meares-Irlen/Visual Stress Syndrome (which can also cause reading, writing and/or attention problems) has been relatively under-researched. Although this poorly-understood condition still attracts a degree of controversy, there is now sufficient peer-reviewed evidence indicating that its prevalence likely exceeds those of dyslexia and ADHD combined. Given that reading, and writing, are known to involve complex phonological processes, it is perhaps quite easy to forget that the crucial first step in the reading process begins when the retina receives photons reflected off the written page, and moreover, that this is greatly influenced by three external factors: 1) The amount of illumination; 2) The spectral properties of the illumination; and 3) The reflectance properties of the page being read (i.e. brightness and contrast). These three fundamental factors, which are essential to optimal visual comfort, thus reading efficacy, have changed significantly in classrooms over the past two decades. Here we examine the details and magnitude of such changes, and also hypothesize that visual and reading discomfort in schools (due to increasingly "brighter" and "whiter" fluorescent lighting and visual media) may be a latent dynamic in recent statistical trends indicating declining levels of student-literacy in many OECD nations, trends that remain unexplained and, despite vast monetary interventions, appear to be irreversible.