Less than two months after being released from the hospital, Ebola survivor Dr. Ian Crozier developed intense pain and fading vision in his left eye, which to his horror changed from blue to green. Doctors found Crozier's eye awash with the Ebola virus, which they had initially thought he was clear of, The New York Times reports.

Though it is quite rare for eye color to change so dramatically, this does happen from time to time as a result of viral infections and is usually permanent. Changes in color are usually due to the viral infection damaging pigmented cells in the iris. Following treatment, however, Crozier’s eye returned to normal, though it remains unclear why.

“I’ve been doing what I do for 40 years and I’ve never seen such a reversibility,” said Dr. C. Stephen Foster, a clinical professor of ophthalmology at Harvard Medical School and the chief executive officer of the Massachusetts Eye Research and Surgery Institution, to The New York Times.

Crozier’s doctor speculates that the change in eye color could be a consequence of the viral infection that has caused a “transformation” in the metabolism of the iris, which is uniform everywhere. What precisely this metabolic alteration may have been, however, remains a mystery. Foster tells The New York Times that this could happen again to other Ebola survivors.

Since last year’s epidemic, the focus has been on treatment and prevention, and doctors are now being confronted with what’s been described as ‘Post-Ebola Syndrome.’ Crozier and a number of West African survivors report a range of symptoms, such as visual problems and joint, muscle and chest pain, since contracting the virus. As Denise Grady reports, Crozier’s doctors were surprised to find the virus inside his eye because although the virus may be found in semen for months after a patient recovers, other body fluids were thought to stay clear.

Survivors of Ebola in West Africa need help to not only deal with their psychological and social needs, but the pressing problem of physical after-effects of the disease, says The World Health Organization (WHO).

Dr. Margaret Nanyonga, a psychosocial support officer for the WHO in Kenema, has previously called for further information on why these symptoms persist, and whether these symptoms are caused by the disease or the treatment. She has developed an assessment tool that will be used to identify the most common symptoms and establish what can be done to help survivors suffering from these ailments.