Poor Vision, Functioning, and Depressive Symptoms: A Test of the Activity Restriction Model

Good visual capacity is among the most important contributors to the value older individuals attach to their lives (Jopp, Roth, & Oswald, 2008). With advancing age, however, vision-related problems are a common stressor. Recent estimates obtained from the National Health Interview Survey indicate that 17% of individuals 65+ years of age reported having trouble with their vision even with corrective glasses and lenses (Federal Interagency Forum on Aging-Related Statistics, 2008). Much evidence indicates that poor visual function can have adverse effects on the lives and well-being of older adults (e.g., Crews, 1994; Federal Interagency Forum on Aging-Related Statistics, 2008; Horowitz, 2004; O’Donnell, 2005). For example, Wahl, Schilling, Oswald, and Heyl (1999) found that poorer visual ability was related to lower subjective well-being in a sample of older adults recruited through physician practices. Bourque, Leger, Pushkar, and Beland (2007) reported that poor vision was related to lower life satisfaction in a representative sample of older Canadians, and Reinhardt (1996) found a similar relationship in a convenience sample of visually impaired older adults residing in the United States. An especially well-established finding is that poor vision is linked to lower psychological health or emotional well-being, most notably to higher depressive symptomatology. Research indicates that not only are symptoms of depression elevated in older adults diagnosed with diseases of the eye such as age-related macular degeneration (e.g., Casten & Rovner, 2008; Tolman, Hill, Kleinschmidt, & Gregg, 2005) but also that poorer visual capacity in general is reliably linked to more depressed affect in late life. For example, Lupsakko, Mantyjarvi, Kautiainen, and Sulkava (2002) found that higher levels of depressive symptomatology occurred in a population-based sample of visually impaired older adults relative to their nonimpaired peers, and Crews, Jones, and Kim (2006) reported that mild or moderate levels of depressive symptoms are a common comorbid condition among elders who are visually impaired. Numerous other studies with convenience and probability-based samples also have found that older adults who rated their vision to be poorer had higher levels of depressive symptomatology (e.g., Brody et al., 2001; Casten, Rovner, & Edmonds, 2001; Chou, 2008; Femia, Zarit, & Johansson, 2001; Furner, Wallace, Arguelles, Miles, & Goldberg, 2006; Reinhardt, 1996). The current study builds on this body of literature by testing three mediators in the link between poor vision and depressive symptomatology. It uses the activity restriction model of depressed affect (Williamson & Christie, 2009; Williamson & Shaffer, 2000) as the theoretical framework, which explains that an important factor in individuals’ psychological adjustment when faced with life stressors is the extent to which the stressor restricts their normal day-to-day activities. According to this model, disruptions in carrying out normal personal and social activities (e.g., shopping, visiting friends) at least partially account for the link between health-related stressors and emotional well-being. The model thus proposes mediational pathways, whereby life stressors such as chronic physical health problems often contribute not only directly to poorer mental health outcomes but also contribute indirectly via their adverse effects on individuals’ ability to carry out day-to-day routine activities. Such activity restriction, in its turn, contributes to poorer mental health and emotional well-being. The activity restriction model has garnered considerable support in studies on late-life stressors such as chronic pain, family caregiving, and living with breast cancer, demonstrating that the link from such stressors to depressive symptomatology is mediated partially or wholly by declines in physical functioning and/or social engagement (Bookwala, Harralson, & Parmelee, 2003; Bookwala & Schulz, 2000; Williamson, 2000a, 2000b; Williamson & Dooley, 2001; Williamson & Shaffer, 2000). However, the activity restriction model of depressed affect has received little attention in the domain of vision impairment. In this study, we propose that the model offers a theoretically viable explanation for the impact of vision impairment on depressed affect in late life. Based on the activity restriction model, we hypothesize that poor vision contributes to depressed affect not only directly but it also results in more limitations in the performance of personal and social activities that, in turn, contribute to higher depressed mood. Poor vision among older adults has consistently been found to have adverse effects on a wide variety of day-to-day functional domains. Numerous studies have found that poor vision diminishes older adults’ ability to carry out everyday physical activities (e.g., Branch, Horowitz, & Carr, 1989; Crews et al., 2006; Lindő & Nordholm, 1999; Horowitz, 1994; Laforge, Spector, & Sternberg, 1992; Travis, Boerner, Reinhardt, & Horowitz, 2004; West et al., 1997). For example, Gunnel and Nordholm found that reading, writing, and watching television were common functional problems associated with poor vision. In addition, mobility-related problems, such as difficulty with moving about outdoors, driving or using public transportation, and conducting bank-related business, were commonly reported by their visually impaired elderly sample. Travis and colleagues found that older adults with impaired vision reported higher levels of difficulty with instrumental activities of daily living (e.g., selecting/locating and identifying clothing, food items, and money; using a telephone; writing checks; and taking medications) and that these individuals identified these visual problems rather than other health problems as the source of these difficulties. Crews and colleagues also found that older adults who reported visual impairment were more likely to report difficulty performing everyday tasks, such as walking, climbing steps, and shopping relative to their age-matched peers. A functional domain in late life that is particularly adversely affected by poor vision is driving ability (e.g., Horowitz, Boerner, & Reinhardt, 2002; Keay et al., 2009; Satariano, MacLeod, Cohn, & Ragland, 2004). Indeed, studies have reported that older adults often cite problems with their eyesight as the reason they limited their driving or avoided driving altogether (Persson, 1993; Ragland, Satariano, & MacLeod, 2004). An emerging literature also indicates that in addition to contributing to limitations in physical function and driving ability, poor vision can have an adverse impact on social functioning domains, such as social network size, relationship maintenance, and social integration (O’Donnell, 2005; Reinhardt, Boerner, & Benn, 2003; Wahl & Tesch-Romer, 2001). Accordingly, studies have found that poor vision is correlated with lower levels of social integration (Femia et al., 2001), more difficulty engaging in social relationships (Crews et al., 2006), and higher levels of social isolation (Femia et al., 2001). Despite widespread evidence from individual studies linking poor vision in older adults to either their functioning (physical, driving-related, or social) or depressive symptoms, there has been little attempt to examine the interrelationships among these variables simultaneously. We address this gap in the literature by testing these relationships in a single model using the activity restriction model of depressed affect as our guiding framework, which posits that the contribution of stressors such as poor vision to depressive symptomatology is explained at least partially by the impact of poor vision on multiple domains of functioning. In the present study, we tested the role of three mediators—physical limitations, driving limitations, and feelings of social isolation—in the link from vision impairment to depressive symptomatology using both subjective (self-report) and objective (visual acuity test) indicators of vision impairment. Difficulties with performing day-to-day activities have been used as indicators of activity restriction by Williamson (2000b), and feelings of social isolation have received attention in other vision research (Femia et al., 2001). Subjective and objective measures of vision are included in the study because they provide complementary information on visual ability among older adults (Horowitz, 2004) and including both can offer a more comprehensive understanding of the effects of vision on psychological health. We drew data for this study from the National Social Life, Health, and Aging Project (NSHAP; O’Muircheartaigh, Eckman, & Smith, 2009; Smith et al., 2009), a survey-based study of a nationally representative sample of older adults residing in the United States. Consistent with the activity restriction model of Williamson (2000) and Williamson and Shaffer (2000), we tested (a) the direct link from subjective and objective vision to depressive symptoms and (b) the extent to which this association is mediated by functional impairment and social isolation known to result from poor vision. We hypothesized that poor vision—assessed both subjectively and objectively—will be associated with greater depressive symptomatology and that more physical and driving limitations and more feelings of social isolation will at least partially account for this association. We predicted that these relationships would exist after controlling for sociodemographic variables that are known to be related to functioning and depressive symptomatology in older samples such as ours, including age, gender, education level, race, and marital status.