Doctor 'cured' of Ebola months ago found the virus lurking in his eye, which turned from blue to green

Two months after being treated in the US for the Ebola he'd contracted in Sierra Leone, Dr. Ian Crozier found out he still had the virus - in his left eye.

Crozier, who had fallen ill in West Africa while was working as a volunteer with the World Health Organization, was taken to Emory University Hospital in Atlanta for treatment. Before he left the hospital, his blood was tested and found to be free of the virus.

But his eye was not.

Crozier knew something had gone horribly wrong about two months later when he looked in the mirror one morning and saw that one of his eyes, which are normally a bright, baby blue, had turned a dull green.

Crozier returned to the hospital reporting symptoms including deteriorating vision, severe pain and pressure in his eye, The New York Times reports.

A study published Thursday in the New England Journal of Medicine describes Crozier's case in detail. Here are some of the most surprising findings:

• Our inner eyes are partially shielded from our immune systems, allowing viruses to be harbored there. Unlike most of our bodies, the inside of our eyes are partially blocked off from the immune systems so that, in the case of intense inflammation, our vision won't be negatively affected. While this safeguarding mechanism, called immune privilege, is obviously advantageous in most cases, it can have unforeseen effects, like harboring deadly viruses.
• The testes are also protected in part from the immune system. A recent study found that Ebola can stay alive in semen for up to five months.

Crozier was alarmed and unsettled by the news that his body remained infected with Ebola. "It felt almost personal that the virus could be in my eye without me knowing it," he told the Times.

Although Crozier's eye remained infected with the virus, his tears and the surface of his eye were still free of Ebola, which kept him from potentially infecting anyone he came into contact with casually, according to the Times. (The kind of contact an ocular surgeon might have would be a different story.)

The virus was essentially trapped deep within his eye, where it couldn't harm anyone - except perhaps Crozier himself.

How Ebola turned Crozier's eye green

Ebola isn't the only virus with the capacity to change your eye color, the Times reports. Other viruses, like herpes, can do it too, but such a shift is very rare.

Typically in such cases, the virus kills pigmented cells in the iris, the colored part of your eye. Usually, the change is permanent.

In Cozier, though, the normal light blue color returned to his left eye after receiving treatment.

Doctors who spoke to the Times said they think what likely happened was that the virus damaged - but didn't kill - the cells in his left eye. When the cells were properly treated and allowed to recover, they healed and the color returned.

The treatment

One of Crozier's doctors, the infectious disease specialist Jay Varkey, got special permission from the FDA to use an experimental antiviral drug for Ebola, according to the Times. (The doctors declined to provide the name of the drug to the Times).

Doctors also gave Crozier a steroid shot above his left eye that they thought would help to release the drug into his eyeball.

About a week later, Crozier said he began to be able to see a bit better. When he moved his head from side to side, he could occasionally make out the shape of his brother Mark sitting on his hospital bed, as if he were seeing through holes in the obstructions that had been blocking out his sight, the Times reports. Over the course of a few months, Crozier's sight returned and his eye regained its natural blue color.

Doctors aren't sure what exactly cured Crozier.

Varkey told the Times he thought the drugs likely brought down Crozier's symptoms and protected his vision long enough for his immune system to fight off the virus. This is the same method doctors used to help many patients in the US recover from a body-wide Ebola infection, since they lacked a proven vaccine or other treatment.

Post-Ebola syndrome

Crozier's eye infection is not an isolated incident. A wide variety of health problems are emerging in many of the 10,000 survivors of Ebola in the three countries most acutely affected by the virus: Sierra Leone, Liberia, and Guinea.

Aside from the searing pain and color change in his eye, Cozier told the Times he suffers from ongoing pain in his joints and muscles, and a lingering feeling of tiredness. He says he's also experienced some hearing loss. All of these problems, as well as others including headaches and chest pain, have also been reported amongst survivors in West Africa. Health workers aren't yet sure how common these symptoms are or how long they will last in each person; reports are mostly anecdotal.

Many doctors in West Africa have said they would welcome opthamologists and other specialists to examine Ebola survivors to help figure out what's happening, but few have volunteered for the job, according to the Times.

"We need to understand why these symptoms persist, whether they are caused by the disease or treatment, or perhaps the heavy disinfection," Margaret Nanyonga, a psychosocial support officer for the World Health Organization in Sierra Leone, said in a press release.

"At this point we do not have enough information to know exactly what is going on," Nanyonga said.