A recent Scientific Reports study investigated whether visual impairment (VI) affects mental disorders in the older population.
Study: The association between visual impairment and mental disorders. Image Credit: ThomsonD/Shutterstock.com
In 2020, about 1.1 billion people were living with some form of VI, which is a very common preventable disorder. Lifestyle changes and population aging are expected to increase this number in the coming years, and most of the burden is likely to fall on low- and middle-income countries (LMICs).
Besides the economic costs, VI adversely affects various aspects of a person’s daily life. The elderly individuals are more vulnerable as they often have many co-existing problems.
Prior research in Western and high-income countries has investigated the relationship between VI and mental health disorders, such as anxiety, depression, cognitive impairment, and suicide.
VI’s psychological problems have received less attention as this is conceptualized as a physical problem. In Iran, no prior studies have analyzed VI's psychological angle, and the current study is the first to fill this gap.
About this study
Given the absence of evidence and the urgent need for information for healthcare planning, this study explored the relationship between mental disorders and VI using the general health questionnaire (GHQ) to understand the psychological aspects of quality of life.
It comprises 28 questions on physical symptoms, anxiety and insomnia, social dysfunction, and depression, which are scored on a 4-point Likert scale.
The sample consisted of 3,200 subjects, aged 60 years and above, from the Tehran geriatric eye study (TGES).
Presenting visual acuity (PVA), as per the World Health Organization (WHO) guideline, was used to define VI. It was further categorized into blindness and low vision.
Individuals with cognitive problems were excluded from the current study. Furthermore, diabetes was defined based on the HbA1c test, and to get a sense of economic variables, data on 13 household assets were collected. Through self-reporting, alcohol consumption and smoking data were obtained.
Consistent with existing reports, a significant association was noted between VI and depression in the present study. Estimates indicated that depression or anxiety was experienced by about one-third of people with VI.
This association was present even after confounders and background variables were accounted for. Previous research has documented similar findings, i.e., adults with self-reported VI were more likely to develop depression in the future.
It is unclear whether the severity of VI is linked to depression. Some studies have documented that the more severe the VI, the more the chances of developing depression, while others have not found such a link.
The bidirectional nature of the relationship between VI and depression has also been highlighted in previous studies, which have been mainly cross-sectional.
The depression coefficient in people with VI was lowered in the present study by controlling for confounders, such as age, income, and health status.
This suggests the need to study the full set of factors governing the relationship between VI and depression so that the magnitude of the association can be pinned down accurately.
Here, increased anxiety in the presence of VI was also noted, and many researchers have not studied this association. One study documented anxiety in patients diagnosed with glaucoma, i.e., not severe VI.
However, it must be acknowledged that anxiety can be the result of the worry of having to live with a disability. Anxiety levels were also lower in blind people than those with VI, which could be due to the lower participation of blind people in social activities.
Moreover, anxiety levels have been shown to decrease with advancing age. Finally, this study also documented that individuals with VI were less prone to engage in physical activities.
In sum, VI was seen to be associated with an increase in depression, anxiety, and physical symptoms. However, most of the psychological disorders studied here could be due to confounding factors and not VI.
The temporal sequence between mental disorders and VI could not be determined here. One possibility is that VI patients potentially develop more functional problems, which subsequently leads to more mental health problems.
Given that the tool used to measure the study outcomes was not similar to the ones used in previous studies, the findings reported here should be compared to those in other reports with caution.
Further, due to the cross-sectional study design, the temporal sequence between mental disorders and VI could not be determined here. Other factors affecting VI, such as cataracts and refractive errors, were not accounted for.
The study's main strengths were the large sample size and careful examination by a trained and expert team.