There does not seem to be a visual subtype of dyslexia. Though researchers can find individuals with phonological (speech sound) problems, and others, alas, with every sort of problem, it is much harder (but not impossible) to find those with a purely visual origin for their dyslexia.
However dyslexics may have a visual component to their learning difficulty. If this is treated effectively, the way may be smoothed for their alphabetic learning. Currently the work of John Stein at Oxford has shown that slow processing in the pathways of large-bodied cells may cause common problems with both visual and auditory processing. This has reawakened interest in a possible perceptual basis for dyslexia.
Ian Jordan is an optometrist from the north-east with an interest in dyslexia. He points out that, in addition to poor acuity, refractive errors and disease, many other visual difficulties can compound the problems of learning literacy. Among these are tracking problems, pattern glare and discomfort caused by stroboscopic or flickering light.
Professional advice will be necessary to identify and remedy accommodation, convergence, saccadal and pursuit difficulties. Such difficulties may combine with others to influence progress in dyslexia, dyspraxia, dyscalculia and attention deficit disorder.
Now Jordan has joined forces with Desktop Publications and CTP Coil to produce a Visual Tracking Magnifier with accompanying booklet, Visual Dyslexia, by Ian Jordan. The magnifier is a small translucent hemisphere, rather like a snow shaker without the snow. Placed on a line of print, it underlines and magnifies it, while shading slightly the lines above and below. Pattern glare is thus reduced. To provide a grip, the circumference is flattened into 12 sides of slightly brushed plastic.
This will be useful to some, intriguing to many. In the early stages of reading it will solve some problems that children have. Later on, it can be discarded, since reading is a matter of transcending the printed page, just as certain remote tribes are said to be able to see only gradually the figures in a photograph.
Currently pound;25 plus VAT plus pound;2.50 pamp;p for both from Desktop Publications, book alone pound;6. Tel: 01724 734255. Magnifier alone from CTP Coil pound;38 plus pound;1 pamp;p. Tel: 01753 575011.
Martin Turner is head of psychology at the Dyslexia Institute