The results of a groundbreaking global collaboration between 79 ophthalmologists and optometrists, led by Professor Rupert Bourne of Anglia Ruskin University’s Vision and Eye Research Unit (VERU), were published in a special issue of The Lancet .
Professor Bourne led the Vision Loss Expert Group in a systematic review of all published, and several unpublished, sources of worldwide data on vision impairment and blindness from 1980 to January 2012. The findings form part of the Global Burden of Disease Study 2010.
The Global Burden of Disease Study examined 291 diseases and 67 risk factors, covering 21 global regions, to contribute to a broader analysis of comparable estimates of mortality, years lived with disability (YLDs), and disability-adjusted life years (DALYs).
The overall results show that infectious diseases, maternal and child illness, and malnutrition now cause fewer deaths and less illness than they did 20 years ago. Consequently, fewer children are dying every year, but more young and middle-aged adults are dying and suffering from disease and injury, as non-communicable diseases, such as cancer and heart disease, become the dominant causes of death and disability worldwide.
Since 1970, men and women worldwide have gained slightly more than 10 years of life expectancy overall, but they now spend more years living with injury and illness.
Visual impairment accounts for 21.1 million years lived with disability (YLD), or 2.7% of the overall global total. The largest global cause of YLDs from vision impairment is “other vision loss” which makes up 29.5% of the total, primarily from trauma, occupational, and idiopathic conditions. Uncorrected refractive error is second and accounts for 26.5% of vision impairment, while cataracts are the third largest contributor at 22.4%.
Glaucoma and macular degeneration together explain a further 10.7%, and trachoma and onchocerciasis accounted for 2.1% of YLD’s from vision loss in 2010. The majority of blindness and low vision YLDs are concentrated in older ages, especially 45 years and older.
There has been an increase in the absolute number of YLDs from low vision and blindness since 1990, while uncorrected refractive error, trachoma, onchocerciasis, and vitamin A deficiency play a much greater role in Sub-Saharan Africa than in other regions.
Professor Bourne, of Anglia Ruskin University, said: “The overall increase in the number of people suffering from blindness and vision loss is due to the huge population explosion that has occurred during the last couple of decades. However, the Global Burden of Disease findings actually show that this increase is not as large as one would expect given the increasing life expectancy in the world’s population over this time.
“The age-standardised prevalence, which takes into account the changes in life expectancy, of blindness and visual impairment, decreased globally between 1990-2010. This points to the successful intervention in treating cataracts and other forms of blindness and infectious diseases such as trachoma.”
The Global Burden of Disease Study has been funded by the Bill and Melinda Gates Foundation, while a Fight for Sight grant assisted with the statistical modelling of temporal trends of blindness over the past 30 years. It is anticipated this work will greatly assist in the distribution of resources and also serve as an advocacy tool in pursuing the aims of VISION 2020: The Right to Sight, which is a global campaign to eliminate avoidable blindness.
The contribution of vision loss to the Global Burden of Disease Study will be discussed at the Royal Society in London on Friday, 14 December, as well as covered in four papers in The Lancet; the first time an issue of the medical journal has been devoted entirely to one study. For further information, visit http://www.thelancet.com/themed/global-burden-of-disease