The effect of letter-stroke boldness on reading speed in central and peripheral vision

Abstract

People with central vision loss often prefer boldface print over normal print for reading. However, little is known about how reading speed is influenced by the letter-stroke boldness of font. In this study, we examined the reliance of reading speed on stroke boldness, and determined whether this reliance differs between the normal central and peripheral vision. Reading speed was measured using the rapid serial visual presentation paradigm, where observers with normal vision read aloud short single sentences presented on a computer monitor, one word at a time. Text was rendered in Courier at six levels of boldness, defined as the stroke-width normalized to that of the standard Courier font: 0.27, 0.72, 1, 1.48, 1.89 and 3.04× the standard. Testings were conducted at the fovea and 10° in the inferior visual field. Print sizes used were 0.8× and 1.4× the critical print size (smallest print size that can be read at the maximum reading speed). At the fovea, reading speed was invariant for the middle four levels of boldness, but dropped by 23.3% for the least and the most bold text. At 10° eccentricity, reading speed was virtually the same for all boldness <1, but showed a poorer tolerance to bolder text, dropping by 21.5% for 1.89x boldness and 51% for the most bold (3.04x) text. These results could not be accounted for by the changes in print size or the RMS contrast of text associated with changes in stroke boldness. Our results suggest that contrary to the popular belief, reading speed does not benefit from bold text in the normal fovea and periphery. Excessive increase in stroke boldness may even impair reading speed, especially in the periphery.

IURead: a new computer‐based reading test

“…Both reading speed and reading acuity versions used the non‐serifed bold Helvetica font with a stroke width 1.5× that of regular Helvetica, and as shown by Bernard et al ., increasing stroke width by <2× has little effect on reading speed. Helvetica has been chosen based upon the fact that it is not only the most common non‐serifed font, but also, similar to Arial, it has a larger lower case x‐height than other fonts, and thus upper and lower case letters are more similar in size .…”

“…two lines vs three lines or four lines, left justify vs R/L justify). Also, font typeface and letter spacing, font boldness are all essential features of reading tests, but seem only to play a minor role in determining reading speed and acuity. Significantly, font size can be a critical determinant of reading speed as letters approach the acuity limit …”

Reading in the presence of macular disease: a mini‐review

“…He found that the optimum stroke‐with setting improved reading acuity by approximately 10%, but he did not measure reading speed nor did he report what was the average setting of the “optimum” stroke‐width. Chung and Bernard adopted the method used by Bernard et al . to measure how reading speed depends on letter stroke‐width for a group of 10 participants with macular disease.…”

The effect of letter string length and report condition on letter recognition accuracy

“…Each pixel subtended approximately 2 arc minutes at the fixation distance of 0.57 m. Letters were rendered in high contrast (0.84) black lowercase Courier font that subtended 0.4° (lowercase “x”-height, ∼12 pixels) at the fixation distance of 0.57 m. Courier font is a fixed width/monospaced font; as such inter-letter spacing is invariant with character type for a given font size. Furthermore, the choice of standard boldness Courier font represents an optimal stimulus characteristic for that font, with boldness significantly higher or lower than the standard boldness exhibiting adverse effects on reading speed 15 . The screen background was bright white (131 cd m −2 ) for all viewing conditions.…”