When a person’s limb has been amputated, they often report still having feeling in the limb that has been lost. This is called a phantom limb, and roughly 60 to 80 percent of amputees have experienced these feelings, which more often than not are quite painful. Patients who have lost an eye experience similar feelings, including seeing actual phantoms!
Psychologist Laura Hope-Stone and her colleagues from the University of Liverpool conducted a study regarding phantom eye syndrome (PES) amongst 239 patients who had lost an eye, especially those who lost it due to cancer. All of the patients had an eye surgically removed, anywhere from four months to four and a half years prior to the survey. 60% of the respondents to the survey said they had experienced symptoms of PES including pain, visual sensations or even the impression that they could actually still see with the missing eye.
The patients that reported being able to see images with the missing eye stated they most often saw shapes or colours. Some said they were able to see more distinct images: “for example, resembling wallpaper, a kaleidoscope, or fireworks, or even specific scenes and people,” according to the researchers. A few of the patients claimed to see “ghosts”, strangers hovering on the edge of their vision. One of the patients reported that he “saw a figure walking at side of me” while another said she “awoke to find an unidentified standing next to the bed”.
The researchers aren’t sure why these symptoms occur, Hope-Stone says:
There may be a range of causes. Human perception is a complex process. Interactions between [the nerve and brain areas] may contribute to phantom sensations. The exact mechanisms are unclear.
Even if doctors cannot yet say what causes these symptoms, they can warn patients they might experience them, and help the patients prepare for them as best they can.