Silver Book Fact
Around 50% of those with glaucoma are not aware that they have the disease.
Friedman D, Wolfs R, O'Colmain B, Klein B, et al. Prevalence of Open-Angle Glaucoma Among Adults in the United States. Archives of Ophthalmology. 2004; 122(4): 532-8. http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=15078671&cmd=showdetailview&indexed=google