Susan, a bright ten-year-old whose teachers think she could read better, is looking at a list of one-syllable words on a computer screen while wearing a pair of goggles. The goggles contain a series of electronic sensors that track the position of each eye.

Afterwards, a print-out , looking rather like an electro-cardiogram, provides an analysis of her speed and her eye movements. The result is fascinating: Susan’s right eye is tracking the print in great detail, but her left eye moves in a straight line.

Peter Irons of TintaVision, the company that makes the goggles, thinks this may indicate an astigmatism, and refers her to an optician. In the meantime, he gives Susan some overlays to use while she reads. She is to return in six weeks for a re-run.

Irons argues that the eyes take a series of pictures as we read, much like a camera, and that the brain’s visual cortex enhances them, so that the edges of letters are seen as sharp lines. If the two “cameras” sending information to the visual cortex are not synchronised, the picture is fuzzy and reading suffers.

Changing the background to text changes the frequency of the signals the brain receives and enables the eyes to work better together. Once the eyes have started to work together properly, the reader may well be able to read fluently without any assistance from tints.

TintaVision calls poor synchronisation of the eyes “asfedia”, a neologism derived from A for Arrythmic, S for Saccade, F for Fixation in, E for Edge, D for detection, and IA ( a condition ) “Tuning” to select the right background takes 30 minutes to an hour, and costs pound;100 plus VAT per visit. Most people take two to three visits.

Clients range from primary pupils to pensioners, and include more than 3,000 university students.

During my visit to TintaVision’s Peterborough head office, a group of pupils from Linchfield primary school was being assessed, without charge.

Their headteacher, Ken Bunch, had found substantial benefits to a group of 60 pupils assessed last year. The greatest gains were often among pupils who had basic reading skills, but whose speed and fluency were held up.

Teachers felt that several had shown improved behaviour and concentration.

TintaVision has many thank-you letters from students, including some who believe that their degree class has improved as a result. The company claims to provide unique, objective evidence that its approach works. The strongest point in this argument lies in the goggles, a system called Eye Trace 300X, developed by the Polish scientist Professor Yan Ober and marketed by Permobil, a Swedish company that has gone into liquidation.

Individual records from these goggles show clear improvements in the synchronisation of the eyes following tuning.

However, TintaVision’s experimental studies are poorly structured, with patchy collection and presentation of data: one study in a secondary school did not record whether final tests were carried out with or without overlays.

Testimonies to the success of the system are similar to those received by other specialists. Helen Irlen, the Californian psychologist who introduced precision tinting into this country in the mid-1980s, seems justified in her claim that other systems have made no improvements on hers.

TintaVision’s theory that progressive tuning can eliminate the need for further support may or may not be true. In the meantime, there are easier and cheaper ways for schools to investigate tinting.

TintaVision at Nasen: Stand 79

Tinting systems: research and resources

Reading through Colour. By Arnold Wilkins (Wiley pound;16). Professor Wilkins is head of the visual perception unit at Essex University, and declares an interest as inventor or developer of several items listed below. His book is the most comprehensive survey available of the impact of tinting on reading and headaches, including migraine. It summarises the results of several positive studies carried out in schools. Search for Arnold Wilkins on the Essex University website (www.essex.ac.uk) Intuitive Overlay Screening Kit.

IOO Marketing, 56-62 Newington Causeway, London SE1 6DS, pound;63 inc VAT and delivery. This kit contains two each of 10 overlays in a range of colours including grey, with a well-designed record form. It allows a school to identify pupils likely to benefit from an overlay. The A5 format fits unobtrusively into a typical paperback.

100 Marketing at Nasen: Stand 59

Intuitive Colorimeter. Used by opticians to alter the background to text in a box using the full range of colour. A typical charge would be pound;40 in addition to a normal sight-test fee. Tinted lenses typically cost pound;50 to pound;60, but may be free to children if they find a participating NHS optician. Both this system and ChromaGen (www.chromagenvision.com) offer tinting using contact lenses. The Chromagen system typically costs around pound;400 in addition to the normal cost of testing and lenses. A screening kit for schools is being prepared.

Irlen Institute. www.Irlen.com. Helen Irlen is one of two pioneers - the other is a New Zealand teacher, Olive Meares - who in the early 1980s discovered the effects of colour on reading. Her method consists of initial screening with overlays, leading to precision tinted glasses. There are eight UK centres. Screeners take a training course (pound;300) and can then purchase and use overlays (pound;3 plus postage). Initial screening costs pound;58.75, and full assessment, including tinting, costs pound;313.25. Helen Irlen’s book, Reading by the Colours (Perigee pound;9.65) is a fascinating first-person account of her discovery.

Precision Tinted Lenses and Migraine. By Ragini Patel, Bruce Evans and Arnold Wilkins. Optometry Today, May 16 2003. A ground-breaking study, including several cases of relief from incapacitating headaches.

The Light Barrier. By Rhonda Stone (St Martin’s Press, $24.95) a well-written account by a parent, commended by leading researchers.