The 100 most frequently cited articles, or citation classics, in ophthalmology were published in 13 journals (Table 3), most in the Archives of Ophthalmology (n = 30), followed by Ophthalmology (n = 27), the American Journal of Ophthalmology (n = 11), Experimental Eye Research (n = 7), Investigative Ophthalmology and Visual Science (n = 7), and Survey of Ophthalmology (n = 7). The articles were the products of multi-institutional collaboration (n = 8), multinational collaboration (n = 6), and individual institutions (n = 86). For simplicity, in articles from multicenter study groups, the name of the coordinator was defined as the country or institution of origin. The 100 citation classics originated from 10 countries: United States (n = 86), Australia (n = 3), United Kingdom (n = 3), Germany (n = 2), and Canada, Greece,Japan, the Netherlands, Portugal, and Sweden (n = 1 each). The 100 articles were contributed by 41 institutions. Table 4 lists the leading 10 institutions, with 2 publications or more, led by The Johns Hopkins University in Baltimore, Maryland (16 publications), followed by Harvard University in Boston, Massachusetts (8 publications), and the University of Wisconsin in Madison (7 publications).