The evolution of the broken ring visual acuity test figure.
The evolution of the broken ring visual acuity figure is described, with particular reference to the contributions of Snellen and Landolt. Reference is also made to its recent application in a study of visual performance, where an angular version of the figure is generated on a television screen.
D006801:Humans; D014787:Vision Tests / Q000379:methods*; D014792:Visual Acuity