Remember the myth of Oedipus, where the king of Ancient Thebes stabbed his own eyes after he realized he'd killed his own father and married his mother?

As gory as it sounds, intentionally blinding oneself isn't entirely mythical. Although rare, there have been cases of people seriously injuring their own eyes, and sometimes completely removing them. There's even a technical term, self-enucleation, for the behavior of taking out your eyeballs.

Dr. Matthew Michael Large at the University of New South Wales in Sydney, Australia, and colleagues have analyzed the records of this behavior available, and published several journal articles on the subject. Their latest is in the British Journal of Ophthalmology, appearing this week.

Based on more than 50 reports of self-injury of the eyes over the past 50 years, the scientists argue that it is not necessarily a so-called Oedipal phenomenon; people do not generally harm themselves this way because of guilt regarding incest. Instead, it is a symptom of untreated psychosis, Large and colleagues write.

The authors noted in a 2008 study that in no recorded culture is the eye ritually mutilated; in fact, it is the only external body part for which this is the case.

They analyzed 89 published cases describing serious self-inflicted eye injury by patients with a diagnosis of a psychotic illness. Patients more commonly removed an eye than penetrating it, or inflicting other orbital injuries. “Three patients blinded themselves with air guns and three patients sustained eye injuries in the course of attempting to stab their brains with a pen or pencil," the authors wrote.

Many patients also attempted or engaged in other violent acts: Two had previously committed homicide and there were several reports of serious assaults. And some had also tried other forms of self-mutilation: stabbing themselves in the neck, attempting to amputate their hands, or biting off their own tongues. Two patients attempted to amputate their own penises, and one castrated himself.

They cite a 1984 study in the journal Survey of Ophthalmology looking at 33 case reports, which found that half of them were young women, two-thirds had religious delusions and six cited the same Bible passage from Matthew:

“And if thy right eye offend thee, pluck it out, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell.”

In 94% of the 89 cases, patients had psychotic symptoms related to the eye - for instance, that the eye was evil or had threatening powers. And some believed that to save themselves or others, they had to sacrifice a normal eye. In 76 of the cases, there was a schizophrenia-related diagnosis.

“None of the patients was reported to have self-enucleated for reasons that could be reasonably compared to the story of Oedipus," they write.

Mostly, patients injured themselves before getting treated. And they weren't only Christians of European descent, as some studies have suggested. Chinese, Japanese, Jewish and Muslim patients have also been documented, Large and colleagues write.

Eye injury of this nature is a medical and psychiatric emergency, they write. Patients should always consult with an ophthalmic surgeon immediately, and they should get prophylactic antibiotics and corticosteroids. A doctor should assess patients for vision loss in the other eye if only one eye was removed.

"Although we hesitate to recommend restrictive treatment for any patient, in the situation of a ﬁrst or attempted self-enucleation, 1:1 nursing and the application of ﬁngerless mittens and arm restraints until antipsychotic treatment has taken effect might be the only way to prevent deluded and determined patients from blinding themselves," Large and colleagues write in the new study. "Electro-convulsive therapy has also been described as a useful treatment."

Eye injuries are distinct from other forms of self-injury, which don't necessarily have psychotic roots, say ethnographers Peter and Patti Adler, authors of "The Tender Cut: Inside the World of Self-Injury." Cutting oneself and similar methods of self-harm are often motivated by troubled feelings, and see injuring themselves as a way to self-soothe, self-punish, or express inner bad feelings. Teenagers and adults experiencing these feelings are also known to engage in self-injury, as well as disadvantaged populations.

"People with serious psychological problems may self-injure, but at this point in time there are many, many more people who self-injure because their lives are tough and they don't know other ways of dealing with it," Adler and Adler told CNN in an e-mail.

But injury to the eye signifies more serious psychological problems, experts say. "Although to the naked eye these behaviors may appear related, they are probably not that close," the Adlers said.