Rose-tinted lenses

In a previous post – https://colourware.wordpress.com/2009/07/04/colour-blindness-news/ – I expressed sceptisism about whether coloured contact lenses or spectacles can improve colour discrimination in colour-blind observers. Today I came across a related story about the use of coloured lenses to improve reading in some people suffering from migraines and/or learning difficulties. It seems to be news in Australia – http://www.theage.com.au/lifestyle/wellbeing/tinted-lenses-bring-words-into-living-colour-20090712-dhfe.html – but I have been aware of research that coloured transparencies can help with reading for many years now. Apparently certain people respond better with certain colours – but I wonder why?