Reading speed in the peripheral visual field of older adults: Does it benefit from perceptual learning?

Abstract

Enhancing reading ability in peripheral vision is important for the rehabilitation of people with central-visual-field loss from age-related macular degeneration (AMD). Previous research has shown that perceptual learning, based on a trigram letter-recognition task, improved peripheral reading speed among normally-sighted young adults (Chung, Legge & Cheung, 2004). Here we ask whether the same happens in older adults in an age range more typical of the onset of AMD. Eighteen normally-sighted subjects, aged 55 to 76 years, were randomly assigned to training or control groups. Visual-span profiles (plots of letter-recognition accuracy as a function of horizontal letter position) and RSVP reading speeds were measured at 10° above and below fixation during pre- and post-tests for all subjects. Training consisted of repeated measurements of visual-span profiles at 10° below fixation, in 4 daily sessions. The control subjects did not receive any training. Perceptual learning enlarged the visual spans in both trained (lower) and untrained (upper) visual fields. Reading speed improved in the trained field by 60% when the trained print size was used. The training benefits for these older subjects were weaker than the training benefits for young adults found by Chung et al. Despite the weaker training benefits, perceptual learning remains a potential option for low-vision reading rehabilitation among older adults.

Reading performance in middle-aged adults with declines in accommodation

“…Therefore, it would be likely that several age-related changes (not only declines, but also improvements) could be observed in reading. In fact, a few studies have shown an age-related decline in reading (Akutsu et al, 1991;Yu et al, 2010), although the effect has been less pronounced than those shown in other areas of visual performance. A recent study, on the other hand, reported that reading performance and contrast sensitivity for presbyopes were improved by perceptual learning without changing the optical characteristics of their eyes (Polat et al, 2012).…”

“…For example, Akutsu et al (1991) found that elderly participants who did not suffer from eye disease (60-74 years of age) read as fast as young participants for character sizes ranging from 0.3°to 1.0°. Yu et al (2010) reported that training to enlarge visual span could improve reading speeds for older adults as much as it did for young people, although several minor differences could be observed between the young and older groups. In contrast, the present study demonstrated that reading performance among the middle-aged was clearly degraded for the nearviewing condition (35 cm).…”

“…A few studies have demonstrated an age-related decline in reading (Akutsu, Legge, Ross, & Schuebel, 1991;Yu, Cheung, Legge, & Chung, 2010), although the effect has been less pronounced than those in other areas of visual performance. Akutsu et al investigated the influence of character size on the reading speeds of elderly participants (aged 60-74 years) by using a drifting-text method.…”

“…The authors considered that agerelated losses in contrast sensitivity for higher and lower spatial frequencies might explain these results. Yu et al (2010) reported that training to enlarge visual span (i.e., the number of characters on a line of text that can be recognized accurately in one fixation) improved reading speed among older adults (ages 55-76), although the training effects were a little weaker for older than for younger adults (Chung et al, 2004).…”

“…In general, aging of the optical and perceptual systems leads to declines of visual function. In the aforementioned studies on age-related declines in reading (Akutsu et al, 1991;Yu et al, 2010), the participants' eyes were corrected by glasses or contact lenses so that the authors could single out decline of the perceptual system in terms of reading. Thus, it is yet unclear psychophysically how aging of the optical system can affect reading performance.…”