Colored Overlays - Does Size Matter?

Abstract of research article: How Big Does a Colored Overlay Have to Be? (Waldie, Michelle; Wilkins, Arnold)

Colored overlays and colored lenses can both increase reading speed, but when they do their color is not necessarily the same, suggesting that the beneficial effects of a colored filter might depend upon the area of the visual field that it colors. We investigated the effects of overlays on reading speed and varied the size of the overlay and the color of the surround. Children who had been assessed with colored overlays were required to read a passage of randomly ordered common words. The words were printed in black ink as a block of text positioned centrally on an A4 page of white paper in landscape orientation.

The speed of reading was compared under four conditions: (1) without an overlay; (2) with an overlay of the chosen color covering the entire page; (3) with the overlay cut so that it just covered the text but left the margin white; (4) with the overlay of the chosen color covering the text but with the margin colored a complementary color, using a second overlay. The children who were using an overlay read more quickly with the overlay; those who were no longer using the overlay did not. Although the block of text covered less than half the page, the color and nature of the margin did not affect reading speed significantly.

These findings suggest that in order to be effective at improving reading speed an overlay needs to cover the text, but not necessarily the remainder of the page, which means that smaller overlays may sometimes be sufficient.

Authors: Waldie, Michelle; Wilkins, Arnold

Source: Ophthalmic and Physiological Optics, Volume 24, Number 1, January 2004 , pp. 57-60(4)

Publisher: Blackwell Publishing