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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. A paper published on 2 August, 2017 in the Lancet provides the latest global estimates of the prevalence of blindness and visual impairment in the world; 
  • 36 million people who are blind
  • 217 million people with moderate or severe distance vision impairment
  • Of those with blindness and MSVI, 124 million people have uncorrected refractive errors and 65 million have cataract—more than 75% of all blindness and MSVI is avoidable
  • 253 million people blind or vision impaired (in 2015)
  • 1 billion people with near-vision impairment
  • The prevalence of blindness and vision impairment combined has dropped from 4.58% in 1990 to 3.37% in 2015.
  • 89% of vision impaired people live in low and middle-income countries
  • 55% of moderate or severely vision impaired people are women
  • Top causes of visual impairment: refractive errors, cataracts and glaucoma
  • Top causes of blindness: cataracts, glaucoma and age-related macular degeneration
  • The number of people visually impaired from infectious diseases has greatly reduced in the last 20 years
Source: IAPB

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%).