The legibility and readability of a visual display unit at threshold

Abstract

As the limit of visual acuity is approached, the need to format text correctly increases. Involved with correct formatting is the use of the letter case most suitably formed to enhance the readability of the text. A series of legibility tests and readability tests were carried out on 20 subjects. The aim of the tests was to provide information on the most suitable case to use for a visual display unit which had to be read at a distance. When letters were displayed singly, upper case was more rapidly and more accurately read than lower case. However, when text was being displayed, there was no significant difference between the reading of upper case and lower case characters. It is recommended that lower case characters should be used for general text with upper case for highlights and that upper case characters should be used for single-letter displays.