Does visual angle of a line of characters affect reading spped?

Abstract

Eighteen participants each proofread 12 three-page articles. Each article was printed at six sizes (or scales) and in two different character sets. Reading distance was constant (52 cm). The lines of characters on the pages subtended 6. 7, 10. 6, 16. 0, 24. 3, 36. 4, and 53. 4 deg at a participant's eye. Proofreading speed and accuracy were reduced at the extreme visual angles. Within a range of at least 16 to 36 deg, proofreading speed and accuracy were unaffected. The significance of these findings is that people's reading efficiency is invariant over a large range of normal viewing. Most printed text and text shown on computer terminal screens form visual angles within this range. Therefore, differences in visual angle probably do not account for the slower reading speed found when people read from CRT displays than from paper.