Optography
Collier's New Encyclopedia (1921)
in optics, the temporary retention in certain cases of an image, that of the last person or thing seen, on the retina of the eye when a man or a beast dies. OPTOMETRY. The science of measuring the vision and strength of the eye without the dilation of the pupil by the use of drugs, and the selection of proper lenses to correct defective vision. The use of drugs to dilate the pupils while making an examination is not legal, except by a registered physicianan oculist. The profession of optometry has been established by those opticians who desired to place their work on a higher plane than that occupied by the ordinary seller of optical goods. An organization was formed in 1904, and committees appointed who worked for legislative regulation of the practice of their profession. Minnesota was the first state to acknowledge the new profession, but now almost every state, as well as the Canait by legislative action. The general requirements for the practice of optometry are a thorough knowla certain amount of high school work. Some colleges, notably Columbia, California, and Ohio State University, as well as the Rochester Athenium and Mechanics Institute, give training for this ing this subject work, and schools teaching alone have been established in Boston, New York, and Philadelphia. Test cards of graduated letters, cases of assorted lenses, and specially designed instruments, usually reflectors or refractors of light, are used in making the tests, the instruments having the widest use being the skiascope, the ophthalmometer, the ophthalmoscope, and the phorometer. Various test lenses are placed before the eye which is being tested, until the lens which best corrects a certain determined defect is secured.
What Has Changed in the Last Century
Collier's states in 1921 as plain fact that the retina temporarily retains "the last person or thing seen" at death — an idea that came from Wilhelm Kühne's experiments of the 1870s, in which he bleached patterns into excised rabbit retinas and called the results optograms. What Kühne actually demonstrated was that rhodopsin, the light-sensitive pigment of the rod cells, can be bleached in a rough pattern under laboratory conditions on a freshly removed eye; it never followed that a murderer's face could be read from a victim's eye. Police in Germany did test the idea in criminal investigations into the 1920s, and it produced nothing usable; the retina begins breaking down within minutes of death and modern forensic science gives optography no standing at all. Today the word survives mainly as a plot device in detective fiction rather than as a branch of optics.
Written for this edition, 2026.