Ebola’s Ocular Impact

NEI Team in Liberia Investigates Ebola’s Ocular Impact

After the 2014 Ebola outbreak in West Africa that took the lives of more than 11,200 people in the region, the National Eye Institute (NEI) deployed a team of clinicians and technical experts to Monrovia, Liberia, to investigate the long-term effects of the Ebola virus on the eye.

retinal layers


Researchers can get a much closer look at an image of potential retinal abnormality taken by slit lamp (left) by zooming in to look at the retinal layers with optical coherence tomography. These detailed images will help document changes to the eye over time.


NEI’s investigation is part of a larger study called PREVAIL III (Partnership for Research on Ebola Virus in Liberia) aimed at understanding the long-term health implications of Ebola virus disease among people who survived acute infection with the virus. Many of the survivors report a variety of ailments from headaches and tinnitus to joint and muscle pain, eye fatigue, and blurry vision.

Although physicians have some understanding about how to manage the infection during the acute phase, their strategies are experimental, and much is still unknown about the natural history of Ebola virus, including how it behaves in the eye and its long-term effects on ocular health and vision, said Rachel Bishop, chief of NEI’s Consult Services Section and part of the NIH team working in Liberia. She recently coauthored a Viewpoint essay on Ebola and the eye that was published online first in JAMA Ophthalmology (JAMA Ophthalmol DOI:10.1001/jamaophthalmol.2015.2400).

Ebola virus lingers in the eye after a person has recovered from the acute illness and the blood is virus-free, a fact that Bishop emphasizes does not put other people at risk of becoming infected because the virus is inside the eye, not on the surface. Nor is there any evidence that live virus is present in survivors’ tears. But transmission associated with the eye could be a potential concern in the future if eye surgery should be needed.

Based on reports from the 1990s, scientists anticipated that people who survived the latest Ebola epidemic would develop uveitis, an inflammatory eye disease. However, “at this point we don’t know the extent of the effect of Ebola on the eye,” said Bishop. “We’ve seen changes to nearly every part of the eye, and some survivors are having vision problems such as difficulty focusing and eye fatigue, the causes of which remain elusive.” Some Ebola survivors show signs of cognitive changes after the infection, which could also contribute to vision difficulties, she added.

The National Institute of Allergy and Infectious Diseases sponsors PREVAIL III in partnership with the Liberian Ministry of Health. The study will be conducted at multiple sites in Liberia. The plan is to enroll up to 7,500 people: 1,500 survivors and up to 6,000 of their close contacts to serve as a control group. The study will help determine whether survivors develop immunity from future Ebola infections, and it will assess the risk of transmitting the virus to close contacts and sexual partners. In addition to the eye, the virus persists in the testes, and semen can carry live virus months after recovery and clearance of the infection from the blood.

A floor of the John F. Kennedy Medical Center in Monrovia was renovated to establish medical facilities for PREVAIL III. Along with Allen Eghrari, from the Johns Hopkins University Wilmer Eye Institute (Baltimore), the NEI team oversaw the design of an eye clinic, which is outfitted with state-of-the-art diagnostic equipment that allows the investigators to document changes in the eye. The team will travel back to Liberia periodically and is assisted by a local eye-care team that includes nurses, technicians, and administrative support staff. Liberian ophthalmologists provide follow-up care for participants needing treatment.

“Despite the tragedy that the Liberians have endured, you get a sense of positive energy and liveliness, so it’s actually a happy place to work,” said Bishop. “It’s a true collaboration.”