Behold the "international eye chart" designed by George Mayerle, a German optician who made his name working in San Francisco in the 1890s.

Optometry was a new field back then, filled with all manners of quackery, some of which Mayerle himself engaged in. (He enthusiastically sold "Mayerle's Eyewater", something he claimed was "the Greatest Eye Tonic".) But optometry was also professionalizing and becoming more research-based, and Mayerle himself pitched in by creating an eye chart designed to be used by people from a wide variety of backgrounds.

San Francisco was, back then, a hotbed of immigration, and Mayerle wanted to serve the city's polyglot community. The goal was to produce a single chart that would allow an optometrist to do an eye-test for nearly anyone who walked in the door:

His eye chart, which he claimed to be “the result of many years of theoretical study and practical experience, ” combined four subjective tests done during an eye examination. Running through the middle of the chart, the seven vertical panels test for acuity of vision with characters in the Roman alphabet (for English, German, and other European readers) and also in Japanese, Chinese, Russian, and Hebrew. A panel in the center replaces the alphabetic characters with symbols for children and adults who were illiterate or who could not read any of the other writing systems offered. Directly above the center panel is a version of the radiant dial that tests for astigmatism. On either side of that are lines that test the muscular strength of the eyes.

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