An article in Ekşi Şeyler hit the agenda like a bomb. According to the article, scientists in the seventeenth century tried to extract an image that formed on the retinas of the eyes of dead people.
This study, called optometry, was done because scientists at the time believed it was possible for the eye to capture our last vision at the time of death. However, it can be said that this idea emerged largely after the invention of cameras and photography.
Many experimental animals were used
In 1876, a German physiologist named Franz Christian Paul discovered rhodopsin, a light-sensitive protein found in the rod cells of the retina that functions just like the nitrates in a camera plate. When this detected protein was exposed to light, bleaching occurred. Because Paul’s life ended early, he was unable to see the impact his work had. Later, another German physiologist, Wilhelm Kuehne, followed up on this theory and began conducting various experiments. In his experiments, he used a large number of animals. He removed the animals’ eyes immediately after death and exposed them to various chemical substances to fix the image on the retina. After these experiments, he discovered that the best substance was potassium alum, which is a type of alum. Salt we call alum.
A rabbit was tied with its head facing a barred window. From this position, the rabbit could only see the window and the cloudy sky. The animal’s eyes were covered with a cloth for several minutes to acclimate it to the dark, i.e. to allow rhodopsin to accumulate in its rods. The animal was then exposed to light for three minutes. He was then immediately beheaded and his eyes removed. An incision is made in the removed eyes, and the back half of the eyeball containing the retina is removed and immersed in an alum solution for fixation.
The next day, Kuhne saw an image of a window with a clear pattern of bars imprinted on the retina with bleached, unmodified rhodopsin: After these studies, Kuhne wanted to conduct his experiments on a human, so in 1880, Kuhne’s eyes were removed from a death row inmate named Erhard Gustav. Reeve was executed after his execution and was handed over to Kuhne’s laboratory at the University of Heidelberg.
Years later, in 1975, the Heidelberg police wanted to re-examine Kuhne’s experiments and results using modern scientific techniques, updated information and advanced equipment. For this reason, they turned to the expertise of Evangelos Alexandridis from Heidelberg University. In a manner reminiscent of Kuehne, Alexandridis was able to create many different high-contrast images from rabbits’ eyes. But he concluded that optics had no potential as a forensic tool.