In one study, individuals age 80 and older made up 8% of the population, yet accounted for 69% of cases of blindness.
Congdon, Nathan G., Benita J. O'Colmain, Caroline C.W. Klaver, Ronald Klein, Beatriz Munoz, David S. Friedman, John Kempen, Hugh R. Taylor, Paul Mitchell, and Leslie Hyman. Causes and Prevalence of Visual Impairment Among Adults in the United States. Archives of Ophthalmology. 2004; 122(4): 477-85. http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=15078664