Anita Lightstone (
Tamsin Lightstone (
Some individuals
read more fluently when the page is covered by a coloured sheet of plastic (an
overlay), or when coloured lenses are worn. Overlays provide a surface colour
whereas lenses mimic a change in the colour of a light source. In 92 patients
attending the Specific Learning Difficulties clinic at the
1. the overlay chosen from
among the 10 IOO Intuitive Overlays
2. the chromaticity
co-ordinates of the lenses subsequently chosen using the Intuitive Colorimeter.
There was no
significant relationship between the chromaticity of the overlay and that of
the lenses. In a second study, patients were given overlays to use for two
months. Nineteen who derived benefit were examined using the Intuitive
Colorimeter. Patients were asked to read aloud randomly ordered common words
(Wilkins Rate of Reading Test):
1. with no colour
2. with the chosen overlay
3. with lenses matching the
chosen overlay
4. with lenses matching the
Colorimeter setting.
The aids
increased reading rate significantly only in conditions (2) and (4) suggesting
central mechanisms for the effects. Coloured overlays give no reliable guide to
optimal lens colour.