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Vision Atlas and VLEG data - FAQ

How does the 2020 version of the Vision Atlas compare to the previous version (2017)?

There are several key differences:

  • The new VLEG data features a dramatically enhanced data set to improve the accuracy of the estimates. This update incorporates data from 512 studies in 112 countries to estimate distance vision impairment, an addition of 224 studies (including data from a further 14 countries).
  • Previously, mild vision impairment was modelled by extrapolating from moderate or worse distance vision estimates due to lack of data. However, in this update, data from 59 studies were available to separately estimate mild vision impairment.
  • Finally, 25 studies were used to estimate for vision loss from uncorrected presbyopia, compared to 18 last time.
  • The maps have a new design and the data can be accessed via several filters. We feature a new narrative, telling the key stories behind the Vision Atlas, providing a rich mix of information and new evidence.

Where can I access the source data?

The VLEG data will be published in The Lancet over the coming weeks and months. The first VLEG paper is currently in preprint with The Lancet.

The IAPB Vision Atlas also hosts the currently released prevalence data. It will also host prevalence data all the way back to 1990.

Will IAPB be adopting these new estimates immediately?

This updated version of the IAPB Vision Atlas, launched on World Sight Day (8 October 2020), includes the new VLEG data. From World Sight Day on, IAPB will be using these new estimates to underpin our communications and advocacy work. We strongly encourage IAPB member organisations to do the same.

Can we compare VLEG data from 2020 with the VLEG data published in 2017?

The new VLEG estimates for 2020 includes revised estimates for the 1990-2010 period from a new model based on an expanded data set. This mean that the 2020 estimates supersede the 2017 estimates. We strongly recommend everyone to use the new data which gives a consistent estimate of the past, present and future numbers.

How does the new data compare with the data in the World Report on Vision?

The estimated number of people with vision impairment in the World Report on Vision was based on data from various sources, including:

  • Distance: VLEG estimates from 2017 on global magnitude and causes of bilateral distance vision impairment and blindness
  • Near: Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia (Fricke et al., 2018)

Estimates of distance and near vision loss in the 2020 Vision Atlas are both based on the 2020 VLEG estimates.