While vision impairment can lead to lower quality of life on its own, the negative impact on daily activities may be even more pronounced for people who also suffer from other chronic health problems, a Korean study suggests.

Researchers examined survey data from more than 28,000 adults and found people with vision impairment were more likely to struggle with mobility, washing, dressing and completing daily tasks, and to experience more pain, discomfort and anxiety than individuals without eye problems.

Struggles with daily life intensified most for people with vision impairment who also suffered from a stroke, arthritis, hepatitis or depression.

"Health-related quality of life is severely decreased when individuals with visual impairment have other additional morbidities," said lead study author Dr. Sang Jun Park.

"What is worse, when vision-impaired individuals have stroke, arthritic conditions, hepatitis and depression, health-related quality of life may decrease much more severely than expected," Park, an ophthalmology researcher at Seoul National University Bundang Hospital, added by email.

Globally, about 285 million people have visual impairment, including 39 million individuals who are blind and an additional 246 million who have low vision, according to the World Health Organization (WHO).

The main causes of moderate and severe vision impairment worldwide are uncorrected nearsightedness, farsightedness and astigmatism, according to the WHO. Cataracts are the leading cause of blindness in low-income and developing nations.

To explore the connection between vision impairment and quality of life, Park and colleagues analyzed data from the 2008 - 2012 Korean National Health and Nutrition Examination Surveys, which include results from eye assessments as well as questions about how well people managed daily activities.

Using the WHO definition of vision impairment, which is approximately equivalent to visual acuity of 20/63 or worse in the better-seeing eye, researchers identified 173 participants with this problem. (Visual acuity of 20/63 is roughly equivalent to needing 1.5-diopter corrective lenses).

The study team looked at 14 common chronic health conditions, including high blood pressure, diabetes, high cholesterol, stroke, heart attack, arthritis, tuberculosis, asthma, kidney failure, hepatitis, depression, cancer, obesity and anemia.

With every one of these conditions, people who also had vision impairment had lower quality of life than those without eyesight problems.

When researchers added up quality of life scores for people with vision impairment and each one of the 14 chronic medical issues, the combined scores were worse than with either condition on its own, with the exception of heart attack survivors.

One shortcoming of the study is the relatively small number of participants with impaired sight, the authors acknowledge in JAMA Ophthalmology. They also note that some of the chronic health conditions examined in the study were also rare among participants.

Even so, scientists are paying more attention to the impact of vision loss on quality of life as the number of people worldwide with impaired sight surges, Jill Elizabeth Keeffe, an ophthalmology researcher at the L V Prasad Eye Institute in Hyderabad, India, writes in an accompanying editorial.

The results from Korea suggest that in many countries, particularly in places with aging populations, many older people and individuals with chronic health conditions may benefit from eye exams, Keeffe told Reuters Health by email.

"As expected, vision loss has an impact on accessing visual information, but we have learnt about risks of falls and concerns about safe mobility, and the ability to participate in education, work, social and leisure activities," Keeffe said.