http://www.who.int/mediacentre/factsheets/fs282/en/
http://www.who.int/bulletin/archives/79(3)227.pdf
http://onlinelibrary.wiley.com/o/cochrane/clsysrev/articles/CD001860/frame.html
http://whqlibdoc.who.int/publications/2010/9789241500722_eng.pdf
http://www.who.int/blindness/causes/priority/en/index4.html
http://www.cureblindness.org/world-blindness
http://www.vision2020.org/main.cfm
http://www.dit.ie/mozambique-eyecare/developmentandeyecare/
http://vision2020.org/main.cfm
http://www.uniteforsight.org/course/trachoma.php?lan=spanish
http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/ accesada 2006