- Globally, at least 1 billion people have a near or distance vision impairment that could have been prevented or has yet to be addressed.
- The leading causes of vision impairment and blindness are uncorrected refractive errors and cataracts.
- The majority of people with vision impairment and blindness are over the age of 50 years.
The International Classification of Diseases 11 (2018) classifies vision impairment into two groups, distance and near presenting vision impairment.
Distance vision impairment:
- Mild – presenting visual acuity worse than 6/12
- Moderate – presenting visual acuity worse than 6/18
- Severe – presenting visual acuity worse than 6/60
- Blindness – presenting visual acuity worse than 3/60
Near vision impairment:
- Presenting near visual acuity worse than N6 or M.08 with existing correction.
A person’s experience of vision impairment varies depending upon many different factors. This includes for example, the availability of prevention and treatment interventions, access to vision rehabilitation (including assistive products such as glasses or white canes), and whether the person experiences problems with inaccessible buildings, transport and information.
The one 1 billion people affected includes those with moderate or severe distance vision impairment or blindness due to unaddressed refractive error (123.7 million), cataract (65.2 million), glaucoma (6.9 million), corneal opacities (4.2 million), diabetic retinopathy (3 million) etc.
In terms of regional differences, the prevalence of distance vision impairment in low- and middle-income regions is estimated to be four times higher than in high-income regions. With regards to near vision, rates of unaddressed near vision impairment are estimated to be greater than 80% in western, eastern and central sub-Saharan Africa, while comparative rates in high-income regions of North America, Australasia, Western Europe, and of Asia-Pacific are reported to be lower than 10% (2).
Population growth and ageing are expected to increase the risk that more people acquire vision impairment.
Globally, the leading causes of vision impairment are:
- uncorrected refractive errors
- age-related macular degeneration
- diabetic retinopathy
- corneal opacity
There is some variation in the causes across countries. For example, the proportion of vision impairment attributable to cataract is higher in low- and middle-income countries than high-income countries. In high income countries, diseases such as diabetic retinopathy, glaucoma and age-related macular degeneration are more common.
Strategies to address visual impairment
Effective interventions are available for health promotion, prevention, treatment and rehabilitation to address the entire range of needs associated with eye conditions and vision impairment across the life course. Some are among the most feasible and cost-effective to implement. For example, uncorrected refractive error can be corrected with glasses while cataract surgery can restore vision.
WHO (World Health Organization) response
WHO’s work is guided by the recommendations of the WHO World report on vision (2019) and the resolution on ‘integrated, people-centred eye care, including preventable blindness and vision impairment’ was adopted at 73rd World Health Assembly in 2020. It is expected that by shaping the global agenda on vision, the report and resolution will assist Member States and their partners in their efforts to reduce the burden of eye conditions and vision impairment and achieve the Sustainable Development Goals (SDGs), particularly SDG target 3.8 on universal health coverage,
Source: World Health Organization – February 2021.
Clarification: This text is an excerpt from a published W.H.O. article. See more here