Visual Impairment, catagories, causes and some other facts

According to WHO, globally, in 2002 more than 161 million people were visually impaired, of whom 124 million people had low vision and 37 million were blind. However, refractive error as a cause of visual impairment was not included, which implies that the actual global magnitude of visual impairment is greater.

Also an interesting phenomenon is, since the estimates of the 1990s, new data based on the 2002 global population show a reduction in the number of people who are blind or visually impaired, and those who are blind from the effects of infectious diseases, but an increase in the number of people who are blind from conditions related to longer life spans.

The age distribution is very uneven. More than 82% of all people who are blind are 50 years of age and older, although they represent only 19% of the world's population.

Gender wise, available studies consistently indicate that in every region of the world, and at all ages, females have a significantly higher risk of being visually impaired than males.

More than 90% of the world's visually impaired live in developing countries.

The cause of visual impairment is various. Cataract is the leading cause in the world, except developed countries. Glaucoma is the second leading cause of blindness globally as well as in most regions, with age-related macular degeneration (AMD) ranking third on the global scale. However, in developed countries, AMD is the leading cause of blindness, due to the growing number of people over 70 years of age.