Johannesburg: Around 108 million people in the world - one in every 90 - have correctable vision impairment, according to a new global study.
Uncorrected refractive error (URE) - nearsightedness, farsightedness, and other focusing problems correctable by prescription lenses - is responsible for moderate to severe vision impairment in 101 million people and blindness in seven million people worldwide, researchers said.
"Uncorrected refractive error continues as the leading cause of vision impairment and the second leading cause of blindness worldwide," said Kovin Naidoon from Brien Holden Vision Institute in South Africa.
Refractive error refers to any of the common vision problems causing decreased sharpness of vision, including myopia (nearsightedness), hyperopia (farsightedness), or astigmatism. In developed countries, eyeglasses or contact
lenses are routinely prescribed to correct these causes of impaired vision, researchers said.
But millions of people around the world still have impaired vision or even blindness caused by URE. This potentially correctable vision impairment has a profound
social and economic impact, including limiting educational and employment opportunities for individuals, families, and communities, they said.
For the study, a group of leading optometrists and ophthalmologists specialising in world blindness analysed the best available research on URE. Pooled data from nearly 250 studies performed between 1990 and 2010 were analysed to estimate the number of people affected by blindness and visual impairment due to URE,
including trends in prevalence and differences by region.
URE was the leading cause of moderate to severe visual impairment, affecting an estimated 101.2 million people. It was also the second leading cause of blindness (after cataracts), affecting another 6.8 million.
"In 2010, URE contributed 20.9 per cent of all blindness and 52.9 per cent of all moderate to severe vision impairment," said Naidoon. Age-standardised prevalence rates of blindness and vision impairment due to URE decreased during the period studied.
However, because of population growth, the numbers of people affected increased substantially. Between 1990 and 2010, the number of people with
blindness caused by URE increased by about eight per cent and the number with vision impairment increased by 15 per cent, compared to a 30 per cent increase in world population.
"Our data again emphasises that globally one of the most simple, effective, and cost effective ways to improve the burden of vision loss would be to provide access to affordable adequate spectacles to correct refractive errors with the
appropriate human resources," researchers said.
The findings were published in the Optometry and Vision Science.
