Dr. Snellen's 20/20: the development and use of the eye chart.
D002648:Child; D002675:Child, Preschool; D005260:Female; D049672:History, 19th Century; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009426:Netherlands; D009885:Ophthalmology / Q000266:history; D012573:School Nursing; D014786:Vision Disorders / Q000175:diagnosis; D014787:Vision Tests / Q000266:history; D014792:Visual Acuity