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. 2021 Feb 16;9(4):e489–e551. doi: 10.1016/S2214-109X(20)30488-5

Figure 15.

Heatmap of the world showing the number of primary research studies on vision and eye health, by country, between 2000 and 2019. Countries are coloured differently depending on the number of studies carried out.

Global distribution of research

Number of primary research studies on vision and eye health, by country, done between 2000 and 2019 (studies identified by “explode eye disease” on MEDLINE, July 10, 2020; n=156 954; appendix 1 pp 58–59).