• Visual elements of readability that can either facilitate or adversely affect attentionality, comprehension and recall include typeface, font size, white space, color, paragraphing and margins.
• In comparison to younger people, the difference for light entering an older person’s optical system is as though he or she were wearing medium-density sunglasses in bright light to extremely dark glasses in dim light.
• With advanced age, the lens loses water and becomes stiffer, less flexible, slightly cloudy and yellowed. Reduced elasticity in the lens and a tendency for the cornea to scatter light makes it more difficult for older people to focus their eyes, making reading without eyewear problematic, and for many, even with eyewear.
• As the yellowing increases, the filtering function of the lens absorbs some of the blue and yellow wavelengths, resulting in changes in a person’s perceptions of colors. White objects take on a yellowish cast, blue is harder to detect and may appear to have a greenish tint, blue and green become more difficult to distinguish and dark blues often appear black. In addition, readability scores can either maximize or limit comprehension and recall by older readers.
• A wide consensus holds that a minimum of 16- to 18-point text should be the norm in communications intended for older visitors.
• You should avoid the use of all upper-case text because it affects negatively on readability.
• Information is generally best limited to a few important points communicated simply and explicitly and surrounded by a lot of white space.
• Concrete terms are easier to cognitively process than abstract terms.
• You can generally enhance readability by the use of short lines and indenting paragraphs.
• Using metaphorical images to reinforce the message in the text can be effective, although the pictures should also be concrete rather than abstract.
• Color discrimination declines with aging. Colors appear to be less bright, and contrasts between colors are less noticeable to the elderly person than to a younger person.
• Also, as the aging lens becomes more yellow, transparency of short wavelengths decreases. This results in a reduction in discrimination of blue objects, which often appear gray; blue print and blue background typically appear washed out.
• You should give attention to manipulating color to maximize contrasts to facilitate text discernment. Black on white provides a high level of contrast, while shades of the same color (for example, dark brown on light brown) provide much lower levels of contrast. A virtual universal consensus holds that you should avoid reverse type (e.g., white type over a dark background).
• The use of bright colors such as red, orange, and yellow are recommended over colors from the short wave length color vocabulary.
• Mixing font types and styles on a single page can be problematic. To increase the attention given to the meaning of the content, give less effort into that which goes into word and graphics processing.
• Italic type is 18% more difficult to read than Roman (upright) letters.
• When distractions (e.g., a phrase in a different font than the target text) are randomly placed within the text, a marked disruptive effect on reading occurs. This effect is particularly severe in older adults.
Following the suggestions above will help to increase the visitor’s pleasure quotient and reduce the frustration quotient of your site.