Can coloured filters help reading? Yes they can

Olive Meares first suggested in New Zealand that children with visual reading difficulties might see more easily through coloured filters. This was taken up commercially in the USA and UK. Each child is usually individually prescribed a special colour; so the glasses tend to cost a lot! However the visual magnocellular system is mainly influenced by only yellow and blue light; so only these two colours should make much difference. We have confirmed that indeed only deep yellow or blue glasses are really useful.

We’ve shown that about one third of children with visual reading problems can be helped greatly by cheap yellow, ‘negative blue’, filters. Yellow cuts out the blue end of the spectrum; and thus bolsters the visual magnocellular system that controls the focus and movements of the eyes. So Nicky Ray and Sue Fowler have just finished a randomised controlled trial (RCT) in which they studied dyslexic children who benefited from wearing deep yellow glasses when reading.

They assessed their visual magnocellular performance by testing contrast, motion sensitivity and eye control. They compared these with their reading ability before and 3 months after they had been randomly allocated either yellow glasses or a 'placebo' treatment- a card with a window cut in it, so that only one line at a time could be seen. This was intended to reduce distraction from neighbouring lines, and it has been found to help some dyslexic children a bit.

The children who received the yellow glasses did exceptionally well compared with the placebo. Their contrast, motion sensitivity and eye control improved greatly, so that in just the 3 months their reading increased by 8 1/2 ms, compared with the placebo group who improved by only 3 months. This difference was highly unlikely to have been just due to chance (P < 0.05). The improvements probably occurred because the yellow glasses boosted the performance of their visual magnocellular system.

Another third of children are helped by looking through deep blue filters.  In their randomised control trial Nicky and Sue found that the children who chose blue improved their reading even more than the yellows - by nine months in the 3 months, 6 months faster than those given the placebo.   We believe the blue filters work by boosting the eyes' input to the hypothalamus which controls our night/day responses, our 'diurnal' rhythms. These children often have disturbed sleep patterns and they often suffer from headaches.  Then the blue filters not only help their reading but their sleep and headaches too!