Background
According to the World Health Organisation, 285 million people worldwide are visually impaired, of which 65% is 50 years or older [
1]. Due to an aging population the prevalence of visual impairment in developed countries will only increase in the future. In 2008, 311,000 people in the Netherlands were visually impaired. It is estimated that in 2020 this number will increase by 18% to 367,000 people [
2].
Depression and anxiety symptoms are common in visually impaired older adults. Recent studies suggested that approximately one-third (range 22-42%) of visually impaired older adults experience mild but clinically significant depressive or anxiety symptoms, also known as subthreshold depression or anxiety [
3‐
6]. This is at least twice as high as the prevalence in the general population (10-15%) [
7]. It is important to treat symptoms of depression and anxiety in an early stage, because these are the most important predictors of developing a full-blown depressive or anxiety disorder according to DSM-V criteria, such as major depression, phobic disorders or generalized anxiety disorder [
8]. Studies suggested that loss of vision increases the risk of depressive disorders [
9,
10].
Depressive and anxiety disorders decrease quality of life, the ability to cope with daily life activities and even life expectancy [
11]. Even subthreshold manifestations of depression and anxiety already have adverse consequences for quality of life [
7,
12] and increase health care utilisation [
7]. Depression and anxiety often accompany disabling diseases and aggravate existing disability [
13]. In addition, they may influence factors that are necessary for successful rehabilitation, such as the ability to learn new tasks, processing information and being oriented towards achieving certain goals [
5,
14]. Depression and anxiety (both threshold and subthreshold) often occur together, which causes even more disability and distress in daily life [
15‐
17]. Research has shown that very few older adults experience only depressive or anxiety disorders, without at least some symptoms of the other [
16,
18].
Some studies have shown that interventions aimed at preventing major depression and/or reducing subthreshold symptoms of depression in the visually impaired can be effective. Horowitz et al. (2005) found that variable low vision rehabilitation services, such as counselling and use of optical devices had a small positive effect on the decline of depressive symptoms after two years [
5,
19]. In another trial, with a follow-up period of six months, Horowitz et al. (2006) showed that optical devices that optimise residual vision, as apposed to adaptive aids that involve learning new methods to compensate for lost functions, had a positive effect on the course of depressive symptoms [
20]. Brody et al. (2006) found that a self-management programme consisting of cognitive and behavioural elements including health education and enhancement of problem-solving skills, significantly reduced depressive symptoms in people with age-related macular degeneration (AMD) after six months [
21]. Rees et al. (2007) concluded that self-management programmes for visually impaired adults are a promising way to help address emotional distress [
22]. Girdler et al. (2010) also evaluated a self-management programme in visually impaired older adults and reported significantly less depressive symptoms at 12 weeks in participants who received the programme as apposed to patients who received standard visual rehabilitation services [
23]. Rovner and Casten (2008) found that problem solving treatment (PST), a short behavioural treatment in which participants learn a new method to address problems that interfere with everyday functioning, prevented the onset of depressive disorders in elderly with AMD after two months. However, after six months there was no statistically significant difference in depressive disorders between the intervention- and control group [
24]. To prevent the onset of depression on the long term Rovner and Casten (2008) suggest to either continue treatment in this high risk group after providing PST or focus on preventive treatment for patients that show early signs of depression [
24]. Currently, Rovner and colleagues are performing the Improving Function in Age-related Macular Degeneration study (IF-AMD) in which they are investigating the efficacy of PST compared to Supportive Therapy in preventing depressive disorders [
25]. Margrain and colleagues are currently performing the Depression in Visual Impairment Trial (DEPVIT) to reduce depressive symptoms in visually impaired adults. They are comparing three groups: one group that receives PST with additional self-help materials, one group that is referred to the general practitioner (GP) and one ‘waiting list control’ group [
26].
These studies together suggest that low vision rehabilitation services, self-management programmes and PST can be effective in addressing depressive symptoms and depressive disorders among visually impaired people. However, only a few studies evaluated the effectiveness of such interventions and these studies were only focused on depression and not on anxiety. Moreover, economic evaluations of such interventions are completely missing.
This project aims to design and test the (cost-)effectiveness of a stepped-care programme to prevent the onset of depressive and anxiety disorders in visually impaired older adults (50 years and older) with subthreshold depression and/or anxiety, in three low vision rehabilitation organisations in the Netherlands and Belgium. By reducing symptoms of depression and anxiety, the intervention is expected to positively influence (vision-related) quality of life and adaptation to vision loss. It is an indicated preventive intervention, aimed at persons who show early signs of depression and/or anxiety but do not meet the diagnostic criteria. The aim is to prevent or delay the onset of major disorders and to reduce the severity and shorten the duration of existing symptoms. Stepped-care comprises different treatment components, such as self-help and PST. The general idea is that if the first, less intensive step does not lead to a reduction of symptoms, then a patient moves to a next step which consists of a more intensive and expensive treatment type. This type of intervention is expected to be efficient, because not all patients need the same type or intensity of treatment [
27]. Several randomised controlled trials (RCTs) outside the field of low vision found that a stepped-care intervention can be effective in addressing depression and/or anxiety [
28‐
33]. Furthermore, both the Multidisciplinary guidelines for mental healthcare in the Netherlands as the National Institute for Health and Clinical Excellence (NICE) in the United Kingdom recommend using a stepped-care model to address depression in older adults [
34,
35].
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
RvN conceived of the study and its design. GvR, HC, JB and TM advised in the development of the design. HvdA drafted the manuscript, which was revised by the other authors. All authors read and approved the final manuscript.