Aims To assess the relationship between vision impairment (VI) and major eye diseases, with vision-specific emotional well-being in a Chinese population.
Methods In this population-based cross-sectional study, 3353 Chinese participants aged 40–80 years answered the emotional well-being scale of the Impact of Vision Impairment questionnaire, validated using Rasch analysis. Participants underwent visual acuity testing and collection of sociodemographic and medical data from standardised questionnaires. The relationships between presenting bilateral VI, presence of major eye diseases (cataract, undercorrected refractive error, glaucoma, age-related macular degeneration and diabetic retinopathy) and emotional well-being were assessed using linear regression models. Stratified analyses for age, gender, education and immigration status were conducted to determine if change in β coefficients differed within each stratum.
Results Approximately half of patients (n=1805) had normal vision, and 43% (n=1534) and 3.4% (n=114) had moderate and severe bilateral VI, respectively. Vision-specific emotional well-being systematically worsened as severity of bilateral VI increased (p<0.001). Compared with no VI and no eye diseases, respectively, severe bilateral VI (23%; β −1.84; 95% CI −2.23 to −1.43) and glaucoma (β −1.88; 95% CI −3.00 to −0.76) were associated with a clinically meaningful reduction in emotional well-being. The reduction in vision-related emotional well-being was substantially and significantly greater in men compared with women (p<0.05).
Conclusions Severe VI and glaucoma are associated with substantial decrements in vision-specific emotional well-being, highlighting the importance of preventing progression of vision loss. Evidence-based interventions to improve vision-related coping skills and emotional management for patients with severe VI and glaucoma are warranted.
- Public health
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People with vision impairment (VI) may experience emotional reactions like anxieties, frustration and embarrassment about poor eyesight.1 A recent meta-synthesis found that VI had a profound effect on adults' psychosocial well-being, including fear of further vision loss, feelings of depression and low self-worth.2 Indeed, older adults with VI are 2–3 times more likely to experience depressive symptoms compared with those without.3 Given that poor vision-specific emotional well-being has been found to mediate the relationship between VI and depression,4 understanding the magnitude of the emotional impact of VI at a population-based level is essential to address disruptive emotional functioning.
Population-based studies in Western5 ,6 and Asian7 cohorts have demonstrated reduced mental health in persons with VI, although there are limited data in Chinese people at the population-based level.8 The way people perceive, moderate and express emotions differs between Asians and Caucasians, both in everyday interactions9 and illness and disease.10 Therefore, it is possible that differences in lifestyle, cultural, religious and environmental habits may mean a differential impact of VI on emotional well-being in Chinese compared with Western or other Asian populations. There are approximately 1.5 billion Chinese people globally, with over 4 million living in Singapore alone. As such, they comprise the largest ethnic group (approximately 75% of the Singapore population), with the vast majority of older people having immigrated from China.11 Therefore, an understanding of emotional functioning in Chinese people with VI is vital to inform public policy decisions, including developing vision-related healthcare plans, identifying eye health disparities and allocation of vision-specific resources.
This study investigated the relationship between VI and eye diseases, and vision-specific emotional well-being in participants from the Singapore Chinese Eye Study (SCES) using the emotional well-being scale of the Impact of Vision Impairment (IVI), a vision-related quality-of-life questionnaire.
Materials and methods
Study design and population
Participants for the population-based, cross-sectional, epidemiological SCES (2009–2011) were recruited from a randomly generated sample of 12 000 individuals from the Singapore Ministry of Home Affairs, of which 6752 adults were selected using age-stratified random sampling. In total, 3353 of 4605 eligible individuals (72.8% response rate) participated in the SCES.12 Ethics approval was obtained from the Singapore Eye Research Institutional Review Board and written informed consent was obtained from each participant. The study was conducted in accordance with the Declaration of Helsinki.
Presenting visual acuity (PVA) was measured in the left and right eye separately with participants wearing their usual habitual optical correction (eg, spectacles or contact lenses). A logarithm of the minimum angle of resolution (LogMAR) chart (Lighthouse International, New York, New York, USA) was used at a distance of 4 m. If no numbers were read at 4 m, the participant was moved to 3, 2 and then 1 m. If no numbers were identified on the chart, PVA was assessed as counting fingers, hand movements, perception of light or no perception of light.
Since both eyes are used by patients in real-world situations, we defined three categories of bilateral VI based on PVA: (1) None, defined as having 0.3 logMAR or less in both eyes; (2) Moderate, defined as having 0.3 logMAR or less in one eye and greater than 0.3 logMAR in the other or greater than 0.3 to less than 1.0 logMAR in both eyes; and (3) Severe, defined as having 1.0 or greater logMAR in one eye and greater than 0.3 to less than 1.0 logMAR in the other eye or 1.0 or greater logMAR in both eyes.
Diabetic retinopathy (DR) and age-related macular degeneration (AMD) were graded from retinal photographs, using the modified Airlie House Classification system from the Early Treatment Diabetic Retinopathy Study13 and the Wisconsin Age-related Maculopathy grading system, respectively.14 Glaucoma was classified using the International Society of Geographical and Epidemiological Ophthalmology scheme based on gonioscopy, optic disc characteristics and visual fields results.15 Uncorrected refractive error (UCRE) was defined as at least a 2-line difference between presenting and best-corrected LogMAR in any eye after subjective refraction and/or the presence of myopia or hyperopia.16 Clinical assessment of lens status and the presence of aphakia or pseudophakia were determined with a slit-lamp.
Assessment of vision-specific emotional well-being
Vision-specific emotional well-being was assessed using the 8-item ‘emotional well-being’ scale (see online supplementary table S1) of the 32-item IVI, which was initially developed and validated in an Australian sample with VI.17 In the current study, the IVI was professionally translated into Mandarin and back-translated into English by two different translators fluent in both Mandarin and English. The emotional well-being items ask participants to rate the frequency with which they have experienced various emotional reactions to and concerns about vision loss in the last month (see online supplementary table S1). The emotional well-being scale of the IVI was found to have excellent psychometric properties using Rasch analysis,18 which is a form of item response theory where ordinal ratings of questionnaires are transformed to estimates of interval measures (expressed in log of the odd units, or logits). Higher logit scores represent better vision-specific emotional well-being and vice versa.
Characteristics of the study population were examined using proportions, means, medians, percentiles and SD. Key covariates included age (years), gender, education (no formal education/less than elementary/elementary/high school/college or university), income (<SG$1000, SG$1000–SG$1999, SG$2000–SG$2999, ≥SG$3000/month), presence of comorbidity (ie, angina, heart attack, stroke, thyroid, hypertension, hypercholesterolaemia, diabetes; yes/no); presence of eye condition (cataract, UCRE, glaucoma, DR, AMD, ‘other’ eye condition; yes/no) and severity of bilateral VI.
Chi-square statistics, the t-test and the analysis of variance were used for univariate associations. The emotional IVI scores were fitted to multiple linear regression modelling and t-based 95% CIs for regression coefficients adjusted for sociodemographics, both ocular and non-ocular comorbidities, and other factors found to be associated univariately with emotional scores. Changes in the β coefficients were also converted into adjusted means to obtain the relative changes and presented in percentage form. A difference in the emotional well-being scores was estimated to be clinically important, if the CI limits of their β coefficients were approximately half the SD of the overall mean (±0.92).19 We conducted four stratified analyses to determine if the change in β coefficients differs within each stratum. Stratified analyses were done for age (≤60/>60 years), gender, education (none/formal education) and immigration status. For the latter, participants were defined as ‘first-generation China immigrants’, if they were born in China and their parents were both born in China, or ‘second-generation China immigrants’, if they were born in Singapore and their parents were both born in China.20 All statistical analyses were undertaken using Stata V.12.0 (StataCorp, College Station, Texas, USA).
Sociodemographic and clinical characteristics
Participants' mean age was 59.72 (±9.94) years (49.6% males, n=1662; table 1). Hypertension (59.2%, n=1982), high cholesterol (47.2%, n=1527) and diabetes (15.2%, n=487) were the most frequently reported comorbidities. Mean PVA in the better eye was 0.20±0.21 LogMAR and 0.39±0.42 LogMAR in the worse eye. Fifty-four per cent of patients (n=1805) had normal vision, and 43% (n=1534) and 3.4% (n=114) had moderate and severe bilateral VI, respectively. The overall mean participant's score on the emotional well-being scale was 7.80±1.84 logits (range: −4.21 to 8.81 logits; table 1).
Vision impairment and vision-specific emotional well-being
In our multiple linear regression model adjusting for potential confounders (table 2), emotional well-being scores systematically decreased as bilateral VI worsened (p<0.001). For example, compared with those with no VI, those with moderate bilateral VI had worse vision-specific emotional well-being (β −1.11; 95% CI −0.26 to −0.04, 14%) scores. The relationship was clinically meaningful for the category of severe bilateral VI, where participants reported a 23% (β −1.84; 95% CI: −2.23 to −1.45) decrease in vision-specific emotional well-being compared with those with no VI (table 2). Glaucoma was associated with a clinically meaningful reduction in emotional well-being scores (β −1.88; 95% CI: −3.00 to −0.76, 24%), independent of VI. Those aged 60–69 and 70 years or older had significantly better vision-specific emotional well-being compared with those aged 40–49 years (table 2), although the improvements were not clinically meaningful.
The decrement in vision-specific emotional well-being associated with bilateral VI was similar in those aged under 60 years compared with those aged 60 years and over, between those with no formal education and those with at least primary school education, and between first-generation and second-generation Chinese immigrants (figure 1). However, we found that males with severe bilateral VI had a substantially and significantly greater reduction in emotional well-being compared with their female counterparts (17%; β −2.19; 95% CI −2.78 to −1.60, 28% vs β −1.37; 95% CI −1.95 to −0.80, p=0.026; figure 1).
In our large population-based study of Chinese adults, we found a systematic decline in vision-specific emotional well-being with increasing severity of VI, culminating in a clinically meaningful reduction in those with severe bilateral VI. Men with severe bilateral VI reported significantly greater emotional distress compared with women. In addition, we found an independent association between glaucoma and reduced emotional well-being that was clinically meaningful, even when controlling for bilateral VI. This suggests that the impact of glaucoma on vision-specific emotional well-being is multifaceted and incorporates other aspects of visual function beyond visual acuity loss. Our findings emphasise that broad, preventative strategies to prevent or slow progression of VI in the population are warranted. Similarly, evidence-based psychological interventions to improve coping and emotional functioning are needed for Chinese people living with VI and may protect wider mental health.
Our findings support those of Nirmalan et al, who reported a systematic decline in mental health scores in an older population in rural India as subjects' vision impairment worsened from moderate to severe to blindness.7 However, the association between moderate bilateral VI and vision-specific emotional well-being was not clinically meaningful in our study. This suggests that the magnitude of emotional burden is greatest in those with severe bilateral VI in our Chinese population, highlighting the importance of preventing progression of VI. The importance of eye screening and monitoring in older adults to decrease VI and blindness through diseases such as DR and AMD has been recognised by the Singapore Ministry of Health as part of their 2010 Functional Screening for Older Adults in the Community Clinical Practice Guidelines.
Research from other health areas, such as diabetes, suggests that poor emotional well-being associated with a chronic health problem is an important construct, which may be more commonly experienced than depression and is related to the demands of dealing with the disease and its management.21 In a similar way, poor vision-specific emotional well-being has been found to mediate the association between VI and depression.4 Therefore, our finding that participants with severe bilateral VI have substantially reduced vision-specific emotional well-being is important as it suggests these individuals may be at high risk of developing depression. Multifaceted interventions to improve patients' emotional functioning comprising evidence-based strategies to enhance coping skills and emotional regulation are required. A recent study by our group found that lack of acceptance and greater helplessness relating to low vision led to a lack of perceived capability to engage in problem-focused coping which, in turn, promoted depressive symptoms.22 Targeted interventions that neutralise unhelpful cognitions such as problem-solving treatment have been shown to be efficacious in reducing emotional distress among individuals with low vision.23 Given that cognitive factors such as acceptance/helplessness may moderate the impact of such interventions, other strategies such as Acceptance and Commitment Theory should also be considered.
Given the tendency for emotional suppression in Chinese culture, the high level of emotional burden reported by vision-impaired participants, particularly in men, in this study is noteworthy. Literature on gender differences relating to vision-specific distress is extremely limited, although differences in knowledge of mental illness, preference for professional help and medication and treatment methods in Chinese-speaking Australian men and women have been reported.24 For example, compared with women, men adhered more to traditional views on the causation of mental illness; reported greater endorsement of the ‘deal with it alone’ approach and had greater belief in the efficacy of ‘traditional Chinese medical doctor’ and ‘Chinese herbal medicines’ for persons with severe mental illness.24 Given that, in general daily life patients, especially men, may be reluctant to admit that they are struggling to cope and may instead ‘suffer in silence’, clinicians need to be aware of the emotional difficulty associated with severe VI, and proactively refer patients for counselling if needed. Similarly, public campaigns to reduce stigma associated with difficulty coping may increase the uptake and effectiveness of interventions to improve emotional well-being in patients with VI.
After accounting for VI, glaucoma patients had a substantially greater reduction in overall vision-specific emotional well-being compared with those with other eye diseases. We also found in a related study25 that glaucoma patients reported substantial reductions in mobility and independence, which could explain the considerable emotional burden observed by glaucoma patients in the current study. Other population-based and clinical studies in Asia7 ,26 and the West6 have also found an independent association between glaucoma and reduced psychosocial functioning. That the association between glaucoma and vision-specific emotional well-being was not wholly driven by visual acuity may be because glaucoma affects peripheral field before central vision meaning that most persons with glaucoma do not lose central acuity until late in the course of disease.6 It also suggests that loss of peripheral vision, difficulty with light/dark adaptation and contrast sensitivity may be important contributors to emotional well-being in patients with glaucoma. Our results suggest rehabilitation therapies for glaucoma patients should focus on assisting them to cope with loss of visual function associated with these visual parameters.
Interestingly, older age was independently associated with better emotional well-being in our study, which may be because individuals of working age are more distressed about their vision loss compared with those who are retired. This finding has important implications for identifying those at risk of vision-specific distress and suggests the need for workplace interventions such as assistive technologies, compensatory strategies and employer and coworker training.27
The population-based design and large sample size are key strengths of this study, as is the use of a well-validated, culturally appropriate outcome measure. The use of Rasch analysis to validate the emotional well-being scale of the IVI and provide estimated linear interval measures is another strong aspect of this study. However, the cross-sectional nature of the study means we were unable to explore longitudinal changes in vision or eye diseases in relation to a change in emotional well-being and limits our ability to establish causality. Other measures of visual function such as peripheral vision or contrast sensitivity were not included in our definition of VI as they were not collected for all participants in our study, and these factors could have been associated with our outcome. Similarly, we were unable to adjust for immigration status in our multiple linear regression model as, due to the classifications we used, data were only available for a subsample (n=900) of our population. Given that there were no significant differences between the first-generation and second-generation immigrants in our stratified analyses, this is unlikely to have changed our main findings.
In conclusion, our study showed that severe bilateral VI was associated with substantial and clinically meaningful declines in vision-specific emotional well-being in an adult Chinese population living in Singapore. In addition, glaucoma patients reported an almost 25% decline in vision-specific emotional well-being, which was not explained by visual acuity alone. Public health strategies to slow the progression of VI and multifaceted evidence-based interventions to improve coping strategies and emotional well-being for patients living with VI and glaucoma are warranted.
Contributors EKF initiated the idea for this analysis, interpreted the data and drafted the paper; PGO conducted the data analysis, interpreted the data and contributed to drafting the paper; CS designed the study protocols and provided revisions; C-YC and TYW provided clinical input and provided revisions; REKM interpreted the data and provided revisions; ELL conceived of and designed the study protocol and provided critical revisions to the paper.
Funding This study was supported by grants from the National Medical Research Council (STaR/0003/2008 and CIRG/1417/2015), the Singapore Bio Imaging Consortium (C-011/2006) and the Biomedical Research Council (08/1/35/19/550). EKF is funded by the Australian National Health and Medical Research Council Early Career Fellowship (#1072987). The Centre for Eye Research Australia receives Operational Infrastructure Support from the Victorian Government.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Singapore Eye Research Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Unpublished data will be shared on request.