PhD Thesis: Text Legibility for Web Documents and Low Vision

The University of Memphis
Memphis, TN
December 2002

PDF File Literature Description: This research addresses gaps in 12 disciplines: applied psychology, education, communication, education, educational/instructional technology, human-computer interaction, human factors, information technology/systems, multimodal interface design, performance improvement, universal accessibility, universal (inclusive) design, usability and vision.

ABSTRACT
Reece, Gloria Anne. Ed.D. The University of Memphis. December, 2002. Text Legibility for Web Documents and Low Vision. Deborah L. Lowther, Ph.D. The preferences of normal readers and low-vision readers for two typeface characteristics, serif presence and emphasis, on electronic displays were investigated. The ultimate goal was to gain insight to aid designers in producing legible, effective electronic displays for a wide audience. The effects of three characteristics of low-vision readers, severity of vision loss, region of eye affected by the primary disorder, and the type of vision loss produced by the primary disorder were considered. Strong preferences for sans serif and Roman (i.e., no italics) typefaces were identified and were found to be similarly distributed among the various categories of participants.

Participants in the study viewed a sequence of computer screens that displayed a pair of words in typefaces that differed in one of the two characteristics and selected the typeface that was most legible. The data for each typeface characteristic were analyzed for overall preferences and for any differences in preferences between categories of participants.

One hundred seventy-seven reduced vision readers and 54 normal readers participated in the study. The reduced vision readers were grouped into eight categories according to the possible values of the three characteristics, and samples of each category were obtained. Additional, higher-level, categories were constructed for use in the analysis of the data.

Participants in all categories preferred sans serif typefaces over serif typefaces and Roman typefaces over italic typefaces. Only slight evidence for variation of these preferences across all eight participant categories was found. Additional comparisons of pairs of categories that differed in only one of the participant characteristics indicated no significant variation of the distributions. These results differed from expectations based upon previous studies that were based primarily upon paper displays and normal readers and exhibited varying, conflicting results. The results from this study establish that typeface characteristics for electronic displays have a strong influence on legibility and must be considered separately from legibility for paper documents. Additionally, sans serif, Roman typefaces are strongly recommended for use in electronic documents for both normal readers and reduced vision readers.