Tuesday 12 December 2017 at 17:18
This fantastic eye chart — measuring 22 by 28 inches with a positive version on one side and negative on the other — is the work of German optometrist and American Optometric Association member George Mayerle, who was working in San Francisco at end of the nineteenth century, just when optometry was beginning to professionalise. […]
Source: http://publicdomainreview.org/collections/george-mayerles-eye-test-chart-ca-1907/