Abstract
Purpose :
People with advanced macular degeneration (MD) experience central-field loss and must rely on peripheral vision for reading. Reduced acuity and increased crowding in the periphery contribute to reading difficulty. Two new fonts have been designed specifically for people with MD to increase letter recognition in peripheral vision. Eido emphasizes increased shape differences” (Bernard et al., PLoS 2016), and Maxular RX emphasizes size and boldness (Skaggs et al., https://louisville.edu/art/faculty/steven-skaggs-m.sc). We compared reading performance of MD subjects on Eido, Maxular and three common fonts (Times, Courier, and Helvetica).
Methods :
Nineteen MD subjects, ranging in acuity from 0.12 logMAR to 1.82 logMAR, performed computer-based versions of the MNRead tests rendered with the five fonts. Maximum reading speed (MRS), critical print size (CPS) and reading acuity (RA) were estimated for each font. Lowercase x-height was used as a definition of print size. We also evaluated the influence of two physical properties of the fonts—average letter spacing (horizontal center-to-center letter spacing divided by x-height) and average pattern complexity (squared perimeter divided by ink area).
Results :
Significant font differences were found for the three measures of reading performance. Times showed the fastest maximum reading speed at 1.92 log wpm (83.2 wpm) with Maxular the slowest at 1.84 log wpm (69.2 wpm). Courier and Maxular had smaller critical print sizes, averaging 0.2 logMAR smaller than the others. Maxular and Eido had the best reading acuity, averaging 0.15 logMar smaller than the common fonts. Linear regression analysis showed that spacing explained 94.9%, 77.6%, and 87.5% of the font effects in MRS, CPS and RA respectively. Increased font spacing contributed to slower maximum reading speed, but improved critical print size and reading acuity. Pattern complexity did not have an effect.
Conclusions :
Two fonts, designed specifically for macular degeneration, did not yield faster maximum reading speeds in MD subjects, but did permit smaller print to be read. Increasing font spacing may have competing effects of slightly reducing reading speed but increasing the range of accessible print size.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.