  When communicating critical information to decision-makers, one of the major
challenges in visualization is whether the communication is affected by
different perceptual or cognitive abilities, one major influencing factor is
age. We review both visualization and psychophysics literature to understand
where quantitative evidence exists on age differences in visual perception.
Using contrast sensitivity data from the literature we show how the differences
between visualizations for different age groups can be predicted using a new
model of visible frequency range with age. The model assumed that at threshold
values some visual data will not be visible to older people (spatial frequency
> 2 and contrast <=0.01). We apply this result to a practical visualization and
show an example that at higher levels of contrast, the visual signal should be
perceivable by all viewers over 20. Universally usable visualization should use
a contrast of 0.02 or higher and be designed to avoid spatial frequencies
greater than eight cycles per degree to accommodate all ages. There remains
much research to do on to translate psychophysics results to practical
quantitative guidelines for visualization producers.
