A young woman's eye trouble in Australia is so unique that doctors across the world are questioning whether she's a one-of-kind medical case -- or a psychological one.
For four years, Natalie Adler of Caulfield South, Melbourne, Australia, has suffered from a rare condition where her eyes shut tight for about three days at a time. After the third day, Adler awakens, able to use her eyes again.
"The night before it sets in, my eyes get quite heavy and that is how I know it is coming," said Adler.
When her eyes are closed, Alder said she can only see through a small slit in her left eye. The condition quite literally becomes a real pain in the neck.
"When my eyes are shut, I have a pain on either side of my temples. I feel nausea, and my body aches all over," said Adler. "I have neck pain from leaning back trying to see out of the bottom of my left eye."
Adler, now 21, told the Daily Mail that phenomenon started one night before a school exam when she was 17 years old, and after a sinus and staph infection. It never got better.
Whatever caused the condition, Adler's health care providers say they have not been able to diagnose her.
"It's been about four years ... [and] she's still continuing her treatment," said Catherine Mancuso, an orthoptist who coordinated Adler's treatment plans at The Royal Victorian Eye and Ear Hospital in Melbourne, Australia.
Adler's ophthalmologist declined to make a public comment.
"We're not really sure of the diagnosis," said Mancuso.
Neurologist professors across the globe in the U.S. are equally confused.
"There's nothing that would cause symptoms of a woman to close her eyes for three days, and open her eyes for three days," said Dr. Dean Cestari, a neuro-ophthalmologist at the Massachusetts Eye and Ear Infirmary in Boston.
Cestari, who is an assistant professor of ophthalmology at Harvard Medical School and certified by the American Board of Psychiatry and Neurology, notes that with every patient he sees, he determines if their symptoms are "organic," caused by physical damage to the body, or "a conversion," which is a physical symptom caused subconsciously by an emotional trigger.
Cestari has seen plenty of "organic" disorders that can cause people's eyes to clamp shut. There's a known movement sequencing disorder in the brain called "apraxia of the eyelid opening," or patients may have damage to part of the brain called the CCN, or caudal central nucleus. Then there's the condition called blepharospasm -- a disorder that is the sustained, forced, involuntary closing of the eyelids.
Each of these scenarios could be diagnosed by a series of physical tests, said Cestari. If not, he would go on to the next step of diagnosing a "conversion" disorder.
"If all of the testing is negative, then you must rule out a conversion disorder," said Cestari. "Conversion disorder is always a diagnosis of exclusion."
One way to think of a conversion disorder, Cestari said, is to think about what would happen to a person if they were confronted by muggers on a dark city street.
"Your heart will start to beat faster, your pupils will get bigger, the hair on your arms stands up. Essentially, your body has a physical reaction to a perceived threat," said Cestari.
As with a mugging or a flight and fight response, patients with a conversion disorder have an actual physical reaction caused by an emotional trigger. But, their emotional trigger is buried and subconscious.
"It's pretty common," said Cestari. For example, he has people who temporarily go blind, or patients who suffer "pseudoseizures" which look like epileptic seizures but have no physical basis in the brain.
"It can be hard because sometimes these patients come in with real experiences, they aren't making this up," said Cestari. "But the mind converted a conflict into a physical manifestation."
Yet, Mancuso, who managed Adler's treatment plan for four years, said doctors went down the mental conflict road.
"She's seen neurologists, she's had psychiatric assessment and nobody has been able to put their finger on it," said Mancuso.
Dr. William David, at clinician at Massachusetts General Hospital, is also perplexed by Adler's condition.
"There are all sorts of different types of disorders that can affect one's ability to open one's eyes," said David, who also listed blepharospasm and apraxia.
"But none of these things cycle in these three days on, three days off sort thing; one has to wonder at this point if there's real physiological reason for this," said David, who is also an associate professor of neurology at Harvard Med School in Boston.
In addition to the cycles, David said Adler's pain in her temple and neck do not conform to a diagnosis of blepharospasm, apraxia or other neurological disorders that cause the eyes to involuntarily shut.
"This picture is very curious and unusual," said David. "I've never seen or heard of anything like this."
Although doctors have not been able to diagnose Adler, Mancuso said she is receiving medical help as if she had blepharospasm.
"She's still continuing her [Botox] treatment," said Mancuso. "It seems to be the only treatment that we knew how to administer to Natalie."
Mancuso said the Botulinum toxin (Botox) treatment once mitigated Adler's cycles and helped with her pain, but Adler said the effects have since begun to fade.
"It meant that she could actually have a period of time where her eyes were open for longer," said Mancuso.
When they're closed, "My life is on hold -- I am unable to drive or work," said Adler. "In the beginning, I tried to ignore it but have now learnt to live with it."
Mancuso said she thinks Adler's sprit is a source of inspiration.
"She's a very positive young woman through this," she said.
Mario Conti in Syndey, Australia, contributed to this report.