Age-Related Changes in Contrast Sensitivity in Central and Peripheral Retina

Abstract

Eight young (average age 20.4 years) and eight elderly (average age 64.4 years) observers took part in three experiments designed to study age-related changes in peripheral retinal function. A further eight young (average age 22.3 years) and eight elderly (average age 63.8 years) observers took part in a replication of experiment 3. All observers had normal or better-than-normal visual acuity and no evidence of ocular pathology. All testing was monocular and the eye with better visual acuity was used. In the first experiment contrast sensitivity was measured in central retina and 10 deg temporally, at spatial frequencies of 0.2, 0.8, 2.0, and 5.0 cycles deg-1. Young observers had better contrast sensitivities than older observers, but only at higher spatial frequencies (2.0 and 5.0 cycles deg-1). For both groups, contrast sensitivity was poorer with peripheral presentation of stimuli than with central presentation, but not for the lowest spatial frequency used (0.2 cycle deg-1). In the second experiment observers had to detect the presence of a sharp edge (square-wave luminance profile), while in the third and fourth experiments the target was a "fuzzy' edge (sine-wave profile). Edges were again presented centrally or 10 deg temporally. As expected from the data of experiment 1, young observers were better able to detect the sharp edge than were the older observers in both central and peripheral viewing conditions. For both age groups, edge detection was better during central viewing than during peripheral viewing. However, contrary to expectations based on the results of experiment 1, detection of the fuzzy edge was better for central than for peripheral viewing for both age groups in experiments 3 and 4. The apparent (and expected) equality of performance found in experiment 3 for young and elderly observers in detecting the fuzzy edge was shown to be due to the range of contrast values used. When appropriate contrast values were used in experiment 4, young observers detected fuzzy edges presented in central retina better than did elderly observers. The results of experiment 1 show sparing of the ability to process low spatial frequencies across (i) age and (ii) retinal location, and are discussed in terms of the notion of (i) models of age-related loss of visual function and (ii) cortical magnification. The results of experiments 2, 3, and 4 provide some support for the proposition that the contrast sensitivity of observers may be used to predict their performance on other visual tasks.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of word frequency and visual complexity on eye movements of young and older Chinese readers

“…This effect of visual complexity may reflect changes in the visual abilities of older adults. In particular, older adults typically experience reductions in visual sensitivity, especially for fine detail (e.g., Crassini et al, 1988;Elliott et al, 1995Owsley et al, 1983;Paterson et al, 2013b,c), and increased effects of visual crowding (McCarley, et al, 2012;Scialfa et al, 2013), both of which will impair the processing of text. Moreover, other research suggests that effects of visual crowding are greater for more visually complex characters (Wang et al, 2014;Zhang et al, 2009).…”

“…Indeed, substantial changes in visual abilities occur naturally with older age, and older adults often experience reductions in visual abilities which are likely to affect both visual and subsequent linguistic processing of text (for a review, see Owsley, 2011). This includes a progressive loss of sensitivity to visual detail (e.g., Crassini, Brown, & Bowman, 1988;Elliott, Yang, & Whitaker, 1995;Owsley, Sekuler, Siemsen, 1983), which has been shown previously to affect normal reading performance for alphabetic languages Paterson, McGowan & Jordan, 2013a,b). In addition, older adults typically experience increased effects of visual crowding (McCarley, Yamani, Kramer, & Mounts, 2012;Scialfa, Cordazzo, Bubric, & Lyon, 2013), characterised by reduced ability to recognise visual objects in clutter, especially in peripheral vision (Bouma, 1971; see also Pelli & Tillman, 2008).…”

The effects of interword spacing on the eye movements of young and older readers

“…The findings for unspaced text in those studies may be attributed to older adults gaining more benefit than young adults from the coarse-scale cue for word segmentation and the reduction in crowding of the exterior letters of words that interword spaces provide. Indeed, in comparison to young adults, older adults experience greater effects of crowding, and typically have a reduced sensitivity to fine scale detail which may lead to a greater reliance on coarsescale information (Crassini et al, 1988;Owsley, 2011;Paterson et al, 2013b,c;Scialfa et al, 2012). Importantly, however, the current results show that as long as some space information is present, the eye movement behaviour of older adults is resilient to small changes in interword spacing size.…”

“…Indeed, older adults have reduced sensitivity to fine-scale information and greater effects of visual crowding (Crassini et al, 1988;Owsley, 2011;Scialfa et al, 2012). This may mean that older adults rely especially heavily on interword spaces during reading as these provide coarse-scale cues for word segmentation and reduce the crowding of the exterior letters of words.…”

Mesopic radial frequency contrast sensitivity function for young and older adults

“…Studies on human vision measuring sensitivity to radial frequency stimuli are dispersed, have rarely been conducted on young adults (11)(12)(13) and are non-existent for the older population. Six young adults (19 to 23 years old) and six older adults (60-69 years old) participated in the present investigation.…”