From Wikipedia: Optography is the process of viewing or retrieving an optogram, an image on the retina of the eye. A belief that the eye “recorded” the last image seen before death was widespread in the late 19th and early 20th centuries, and was a frequent plot device in fiction of the time, to the extent that police photographed the victims’ eyes in several real-life murder investigations, in case the theory was true. Although repeatedly debunked as a forensic method, there is a scientific basis behind the idea.

With the theory that the eye retained an image at the moment of death rampant in the Victorian imagination, police investigators in the late 1800s began considering optography as an investigative technique in murder cases. One of the earliest known attempts at forensic optography occurred in 1877, when Berlin police photographed the eyes of murder victim Frau von Sabatzky, on the chance that the image would assist in solving the crime.

In 1888, London police officer Walter Dew—later known for catching the murderer Dr. Crippen—recalled optography being attempted on Mary Jane Kelly in what he called a “forlorn hope” of catching her suspected killer, Jack the Ripper.