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As stated by Smart (2006-2007), "models of disability provide definitions of

disability, offer the explanation for the cause of disability, and present the solution or treatments based on the perceived needs of the individual with the disability" (p. 1). A biomedical model of disability, which has also been labeled as the individual

or ‘personal tragedy theory of disability’ (Oliver, 1990), has long dominated conceptions of disability in medical and rehabilitation science (Imrie, 1997). Underpinned primarily by a positivist epistemology, the biomedical model understands disability as individual pathology, meaning that there is something ‘wrong’ with the individual’s body resulting from disease, trauma, or an accident (Albrecht, 1992). Thus, it is the underlying pathology, impairment, or dysfunction that causes disability (Smart, 2006-2007). Much of the ARVL research has focused on the physiological correlates of vision loss, such as visual acuity, contrast sensitivity and visual field, during various activities and the impact of different management strategies on these correlates (Grue et al., 2008; Laitinen et al., 2007; Owsley, McGwin, Sloane, Stalvey & Wells, 2001; Wong, Guymer, Hassell & Keeffe 2004). For example, Laitinen et al., (2007) completed a cross sectional survey with older adults (N=3439; > 55 years old). The study aimed to determine the effect of decreased visual acuity on activities of daily living, instrumental activities of daily living, and mobility. Data revealed that the

prevalence of activities of daily living (ADL), instrumental activities of daily living (IADL) and mobility limitations increased with decreasing visual acuity (p<0.001). Similarly, Owsley et al., (2001) aimed to identify those IADLs whose completion time was associated with visual function in a sample (N=342) of older adults aged 56-86 years old. Results indicated that poorer scores on visual acuity, contrast sensitivity, and useful field of view were associated with longer visual IADL completion time, such as reading medicine bottles, threading a needle, using a screwdriver, reading ingredients on a can, reading a newspaper article, and inserting a key into a lock.

In addition to understanding disability as individual pathology, the biomedical model of disability ascribes to the tenet of physical reductionism. Physical

reductionism risks failing to acknowledge the influence of context in the disability experience because it frames disability in terms of the body, without considering contributing social, cultural, and environmental factors. As an example of this tenet, McGrath and Laliberte Rudman (2013), aimed to summarize, by means of

a scoping review, what is currently known regarding the underlying factors which influence the activity engagement of older adults with ARVL. The 22-article review revealed how this literature on activity engagement of older adults with ARVL has focused predominantly on the impact of personal factors such as, demographic (age, socio-economic status), emotional (fear, emotional response to vision loss), behavioral (accepting risk, refusing or delaying rehabilitation services), and diagnostic components (degree of vision loss). In contrast, the impact of environmental factors, such as social attitudes regarding vision loss or the physical accessibility of outdoor spaces, have been, for the most part,

negated, downplayed, or ignored. Framing disability as resulting from bio-medical impairment, absolves society from the need to provide environmental

accommodation and instead places the responsibility for managing disability largely upon the disabled individual.

Defining disability solely as a medical problem, lends 'scientific credibility' to the idea that "high levels of expertise, training, and technology" (Smart, 2006-2007, p. 2) are needed to treat, modify, or fix the disabled person so that they can meet the normative standards and demands of Western society. Although treatment of the body is a necessary component of rehabilitation, a focus on the environment is missing from this discussion. This idea is reinforced by two inter-related

doctrines of the biomedical model, namely that of regimen and control and the doctrine of the mechanical analogy (Longino, 1998). For example, the doctrine of regimen and control states that if disease is thought to occur as a result of the body, then the logical focus of treatment is the body. In this sense, disability is seen as needing some form of medical intervention or rehabilitation in order to 'fix' the bodily dysfunction (Devlin & Pothier, 2006) or otherwise bring the individual to as close a state of “normal” as possible (Mitra, 2006). In order to 'treat' the disabled person, their body is viewed as "a system of functionally interdependent parts" (p. 105) meaning that the body is treated as though it operates as a machine and the healthcare provider as the mechanic. Not surprisingly, when visual impairment is detected, the eyes and the associated parts of the visual system are the first bodily structures to examine in order to

determine a cause and a cure. However, in research, this view can be seen as problematic when it is assumed that individual body parts can be treated in isolation from each other as well as from context. Viewed in this mechanistic manner, vision loss is seen as a malfunction of the body that needs to be 'fixed’ in order to restore normalcy. This tenet is reflected in the ARVL literature that is focused primarily on the pathophysiology of vision loss, whereby assistive

technology is conceptualized as a means to replace the functions lost and enable older adults to cope with disabling situations when a cure is neither a feasible nor realistic goal (Copolillo & Teitelman, 2005; Girdler, Packer & Boldy, 2008; Ivanoff & Sonn, 2005; Lamoureux et al., 2007; Moore & Miller, 2003; Pankow, Luchins, Studebaker & Chettleburgh, 2004; Ryan, Anas & Bajorek, 2003; Stelmack, Moran, Dead & Massof, 2007). For example, Fok, Polgar, Shaw and Jutai (2011) aimed to determine the relative importance of assistive technology devices for the performance of daily occupations among 17 adults (aged 30-89 years old). Results tabulated the mean ranking of importance of 21 assistive technologies, including both low tech (e.g., handheld magnifier) and high tech (e.g., CCTV) devices to daily activity performance. There are positive impacts to this work that assumes ‘broken’ body parts (i.e., the eye) require a mechanical ‘fix’ (e.g., lens magnification); however the research agenda can be unintentionally narrowed if it fails to consider issues such as designing everyday technologies for persons of differing abilities. In addition, the primary focus on fixing the body can mean that in situations in which a cure or fix is not possible, the end point becomes the message that ‘nothing more can be done’; meaning that once they have done all that is possible to optimize the eye, biomedical professionals convey that there is nothing else that can be done for the patient with ARVL.

Researchers have long challenged the predominance of the biomedical model and critiqued the limits of its sole use as a model for understanding disability (Hosking, 2008; Hughes & Paterson, 1997; Smart, 2006-2007). In doing so, authors have advocated for the use of alternative models of disability. For

example, Forhan (2009) examined the area of obesity research within the context of the medical, social, and biopsychosocial model of disability and advocated for

the use of the biopsychosocial model as a means of classifying and treating disability related to obesity. The International Classification of Functioning, Disability and Health (ICF; WHO, 2001) is one such biopsychosocial model that has received considerable research interest. It evolved from the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) (WHO, 1980) and is an attempt to more broadly acknowledge that disability is influenced both by personal as well as contextual and environmental factors (Hammell, 2006). The model, however, has been subject to critique both due to its approach of classifying individuals according to their disability (Hammell, 2006; Pfeiffer, 2000), its lack of consideration of the role of the environment in the creation of impairment (Hammell, 2006), and its continued perpetuation of disability as an individualized and medical issue (Pfeiffer, 2000). As will be delineated in the following section, although the social model of disability addresses these primary critiques, it underplays the role of the body in the disability process.

5.3 Key tenets of a social model of disability and its application to