title: Applying new design principles to the construction of an illiterate E chart.
abstract: New design principles have been applied to the construction of an illiterate E chart. A chart can thus be produced in which the only variable in the visual acuity task for letters of different size is the letter size itself. A simple method for using this chart in field studies is described.
mesh_terms: D004522:Educational Status; D005069:Evaluation Studies as Topic; D006801:Humans; D008954:Models, Biological; D012029:Refraction, Ocular; D014787:Vision Tests / Q000295:instrumentation*; D014792:Visual Acuity