The development of visual standards: Snellen, Jaeger, and Giraud-Teulon.
D001317:Austria; D005602:France; D049672:History, 19th Century; D006801:Humans; D009426:Netherlands; D009885:Ophthalmology / Q000266:history*; D014787:Vision Tests / Q000266:history*; D014792:Visual Acuity