Use of coloured lenses, or overlays, has been linked to helping people read for 200 years, but remains controversial because of a lack of robust evidence for its effectiveness (Evans and Allen, 2016). 

Jim Gilchrist FCOptom, co-author of guidance for the Specific Learning Difficulties Assessment Standards Committee and former Head of Optometry and Vision Science at the University of Bradford, says: “There has long been this idea, in many people’s minds, that coloured lenses and dyslexia go handin hand. It’s a fundamentally wrong idea, because coloured lenses in this context are intended to alleviate visual stress not dyslexia, and most people with dyslexia do not have visual stress.