Why do I need a special test to get coloured glasses?
The colour of your tinted glasses will rarely be the same colour as your overlay because the brain processes the effects of overlays and glasses in different ways. When using an overlay, your eyes are adapted to white light, but while wearing tinted glasses your eyes are adapted to everything being coloured not just the page of a book. The test needed to prescribe the colour for the lenses is done with a machine called The Intuitive Colorimeter (for more information: www.ceriumvistech.co.uk and www.essex.ac.uk/psychology/overlays . The machine emulates what it would be like to read text while wearing coloured glasses, it is possible to choose from thousands of shades and hues to arrive at the optimum colour for you lenses.
