The independent effects of luminance and chromatic contrast between text and background on reading speed were examined for normal and reading disabled subjects. The requirement of making eye movements for reading was also manipulated. The factors of chromatic contrast without luminance contrast (equiluminance) and reading without required eye movements (with rapid serial visual presentation, or RSVP) disrupt and minimize, respectively, the need for visual spatial localization of gaze within lines of text. Without luminance contrast, visual perception of spatial position and motion is disrupted to a certain degree. With RSVP, skilled readers can read two and three times faster than with traditional line by line reading. Reading rates were compared across conditions of contrast (high luminance and equiluminance contrast) and of text presentation (RSVP and traditional page format). Adult skilled readers participated in the first study, and groups of average ability and reading disabled children aged thirteen to sixteen participated in the second study. In Study 1, adults read equiluminant contrast text slower than text with a high luminance contrast. The degree of slowed reading under equiluminance was greater when eye movements were required for reading. In Study 2, normal reading was slowed with equiluminance, while disabled reading was not affected by equiluminance. This contrast effect did not reliably distinguish reading ability groups. Also in Study 2, both normal and disabled reading rates increased significantly when eye movements were not required with RSVP text. Normal reading rates were more facilitated by RSVP than disabled reading rates
