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Eye Conditions

Vision loss can be caused by eye problems that are present from birth, by conditions that appear later in life, or by infections or environmental factors.

According to World Health Organization:
  • An estimated 253 million people live with vision impairment.
  • 36 million are blind.
  • 217 million have moderate to severe vision impairment.
  • 81% of people who are blind or have moderate or severe vision impairment are aged 50 years and above.
  • An estimated 19 million children are vision impaired.
  • Of these, 12 million children have a vision impairment due to refractive error.
  • Around 1.4 million have irreversible blindness, requiring access to vision rehabilitation services to optimize functioning and reduce disability.
  • Globally, more than 80% of all vision impairment can be prevented or cured.
  • The major global causes of moderate to severe vision impairment are: uncorrected refractive errors, 53%; un-operated cataract, 25%; age-related macular degeneration 4%; glaucoma, 2%; diabetic retinopathy 1%.
  • The major causes of blindness are: un-operated cataract, 35 %; uncorrected refractive error 21 %; glaucoma 8 %.
  • Overall, the prevalence of vision impairment worldwide has decreased since early estimates in the 1990s.
  • However, it is estimated that the number of people with vision impairment could triple due to population growth and ageing. By 2050 there could be 115 million people who are blind, up from 38.5 million in 2020.
An analysis of the global distribution shows a disproportionately large prevalence of visual impairment and blindness in low-income countries. In these countries, cataracts and trachoma are the greatest causes of avoidable blindness. The lack of access to affordable eye care services in these countries severely aggravates visual impairments and blindness. 

In many middle-income and high-income countries, the main eye conditions are emerging from increasing cases of diabetes which causes an eye condition called diabetic retinopathy. Glaucoma, and age-related macular degeneration (AMD) also rank highest among the global causes of visual impairment. AMD is the primary cause of visual deficiency in high-income countries, as well as uncorrected refractive errors. (
http://www.who.int/blindness/causes/priority/en/)

The leading causes of visual impairment in low income countries, particularly in Sub-Saharan Africa, are cataracts (50%), glaucoma (15%), corneal opacities (10%), trachoma (6.8%), childhood blindness (5.3%) and river blindness (onchocerciasis 4%).