Contrast coding has been reported to differ between dyslexic and normal rea
ders. Dyslexic readers require higher levels of contrast to detect sinewave
gratings for certain spatiotemporal conditions, and dyslexic readers show
faster visual search at low contrast. We investigated whether these differe
nces in early contrast coding generalize to reading performance by measurin
g reading speed as a function of text contrast for dyslexic children and ad
ults and for age-matched controls. Contrast affected reading performance of
dyslexic and normal readers similarly. For both groups, reading speed was
relatively constant between 100 and 2% contrast, and decreased rapidly belo
w 2% contrast. This pattern of results held true for both children and adul
ts, for text with and without sentence context, across a range of character
sizes, and for reading aloud and reading silently. We conclude that earlie
r findings of group differences in contrast effects on grating detection or
visual search tasks do not generalize to reading. (C) 2000 Elsevier Scienc
e Ltd. All rights reserved.