Letter case and text legibility in normal and low vision.
It is thought by cognitive scientists and typographers alike, that lower-case text is more legible than upper-case. Yet lower-case letters are, on average, smaller in height and width than upper-case characters, which suggests an upper-case advantage. Using a single unaltered font and all upper-, all lower-, and mixed-case text, we assessed size thresholds for words and random strings, and reading speeds for text with normal and visually impaired participants. Lower-case thresholds were roughly 0.1 log unit higher than upper. Reading speeds were higher for upper- than for mixed-case text at sizes twice acuity size; at larger sizes, the upper-case advantage disappeared. Results suggest that upper-case is more legible than the other case styles, especially for visually-impaired readers, because smaller letter sizes can be used than with the other case styles, with no diminution of legibility.
Arditi
Aries
A
Arlene R. Gordon Research Institute, Lighthouse International, 111 East 59th Street, New York, NY 10022, USA. arditi@lighthouse.org
Cho
Jianna
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D010364:Pattern Recognition, Visual; D011327:Printing; D011932:Reading; D012684:Sensory Thresholds; D013997:Time Factors; D015354:Vision, Low / Q000503:physiopathology / Q000523:psychology*; D014792:Visual Acuity