are sheets of coloured plastic film suitable for placing over a page of text
when reading. There are several sets on the market. For example, a set is
manufactured by i.O.O. Sales (NB Not
100 Sales), another by Cerium Visual
Technologies and a third by Crossbow
Education. Overlays with a small number of colours are insufficient.
It is necessary to obtain overlays that sample a large number of colours
systematically and efficiently, for example, as in the figure.
The effects of
coloured overlays on reading fluency are reviewed
others involved in the assessment of children using overlays may find additional
instructions helpful. The beneficial effects of the overlays on reading
fluency can be assessed using the Rate of
Reading Test, also available from i.O.O.
Sales and Cerium Visual
Overlays have been shown to be of benefit to many
primary school children. About 5% of children read >25% more quickly with an
overlay. They can be cut down to suit the size
of the text.
You may wish to
check the answers to frequently
asked questions concerning overlays and visual stress.
The figure shows
the spectral reflectances of the Intuitive Overlays, together with their
chromaticities (inner ring of points) and the chromaticities of two overlays
superimposed (outer ring of points). (The spokes connect the chromaticites of
the single overlays with those of two identically coloured overlays
superimposed, and the interstitial points show the chromaticites of two
overlays having neighbouring chromaticity.)