Visual impairment and blindness
- 285 million people are estimated to be visually impaired worldwide: 39 million are blind and 246 have low vision.
- About 90% of the world's visually impaired live in developing countries.
- 82% of people living with blindness are aged 50 and above.
- Globally, uncorrected refractive errors are the main cause of visual impairment; cataracts remain the leading cause of blindness in middle- and low-income countries.
- The number of people visually impaired from infectious diseases has greatly reduced in the last 20 years.
- 80% of all visual impairment can be avoided or cured.
There are four levels of visual function, according to the International Classification of Diseases -10 (Update and Revision 2006):
- normal vision
- moderate visual impairment
- severe visual impairment
Moderate visual impairment combined with severe visual impairment are grouped under the term “low vision”: low vision taken together with blindness represents all visual impairment.
The causes of visual impairment
Globally the major causes of visual impairment are:
- uncorrected refractive errors (myopia, hyperopia or astigmatism), 43 %
- unoperated cataract, 33%
- glaucoma, 2%.
Who is at risk?
Approximately 90% of visually impaired people live in developing countries.
People aged 50 and over
About 65 % of all people who are visually impaired are aged 50 and older, while this age group comprises about 20 % of the world's population. With an increasing elderly population in many countries, more people will be at risk of age-related visual impairment.
Children below age 15
An estimated 19 million children are visually impaired. Of these, 12 million children are visually impaired due to refractive errors, a condition that could be easily diagnosed and corrected. 1.4 million are irreversibly blind for the rest of their lives.
Changes over the last twenty years
Overall, visual impairment worldwide has decreased since the early 1990s. This is despite an ageing global elderly population. This decrease is principally the result of a reduction in visual impairment from infectious diseases through:
- concerted public health action;
- increased availability of eye care services;
- awareness of the general population about solutions to the problems related to visual impairment (surgery, refraction devices, etc.).
The global response to prevention of blindness
Globally, 80% of all visual impairment can be prevented or cured. Areas of progress over the last 20 years include:
- governments establishing national programmes and regulations to prevent and control visual impairment;
- eye care services increasingly integrated into primary and secondary health care systems, with a focus on the provision of services that are high quality, available and affordable;
- campaigns to raise awareness, including school-based education; and
- stronger international partnerships, with engagement of the private sector and civil society.
Data over the last 20 years shows that there has been significant progress in preventing and curing visual impairment in many countries. Furthermore, there has been a massive reduction in onchocerciasis-related blindness as part of a significant reduction in the disease. This has been achieved through a number of successful international partnerships.
Specific achievements include Ghana and Morocco, both of whom have reported elimination of blinding trachoma (2010 and 2007 respectively). Over the last decade, Brazil has been providing eye care services through the national social security system. Since 2009, China has invested over 100 million dollars in cataract surgeries. Oman has completely integrated eye care service provision in the primary health care framework over the last decade and since 1995 India has made available funds for eye care service provision for the poorest at district level.
WHO coordinates the international efforts to reduce visual impairments.
It's role is to:
- monitor the worldwide trends of visual impairment by country and by region;
- develop policies and strategies to prevent blindness appropriate for various development settings;
- to give technical assistance to Member States and partners;
- to plan, monitor and evaluate programmes; and
- to coordinate international partnerships in support of national efforts.
In 2013, the World Health Assembly approved the 2014-19 Action Plan for the universal access to eye health, a roadmap for Member States, WHO Secretariat and international partners with the aim of achieving a measurable reduction of 25% of avoidable visual impairments by 2019.
WHO works to strengthen national and country-level efforts to eliminate avoidable blindness, help national health care providers treat eye diseases, expand access to eye health services, and increase rehabilitation for people with residual visual impairment or who are blind. Building accessible and comprehensive health systems is the focus of this decade.
WHO leads several international alliances of governments, private sector and civil society organizations aiming at contributing to the elimination of blinding diseases. It also provides technical leadership to specific disease efforts which are deployed by its partners or the private sector to eliminate trachoma from the world by the year 2020.
For the last two decades WHO has worked with a network of international partners and private sector to ensure that appropriate, updated, good quality eye care solutions were made available to the people in need.
Since 2004, WHO in partnership with Lions Clubs International has established a global network of 35 childhood blindness centres in 30 countries for the preservation, restoration or rehabilitation of sight in children. This unique and innovative global projects will open 20 additional eye care service centres for the children in new countries. The centres will help combat to fight avoidable childhood blindness and help securing a future with full visual function for the children in need of care.
In response to the increasing burden of chronic eye disease WHO has coordinated the development of research projects and policies for diabetic retinopathy, glaucoma, age-related macular degeneration and refractive errors.
Finally, to support comprehensive eye care systems, WHO continues to provide epidemiologic and public health technical support to its Member States.