By Robert Preidt
The virus is known to cause microcephaly, in which infants are born with a smaller-than-normal head and brain.
And previous research has found that one-third of Brazilian babies with microcephaly have eye problems such as ocular lesions, optic nerve abnormalities and chorioretinal atrophy, a withering of the retina and choroid. The choroid provides oxygen and nutrients to the retina.
Now, this new report on three Brazilian infants with microcephaly identified three new eye problems: retinal lesions, bleeding in the retina and abnormal blood vessel development in the retina. The three infants also had the eye problems found in previous research.
Since last spring, Brazil has been the epicenter of a Zika outbreak, and nearly 5,000 babies have been diagnosed with microcephaly.
In the United States, a total of 279 Zika-infected pregnant women are being monitored, according to two registries that have been created by the U.S. Centers for Disease Control and Prevention.
The virus is expected to become active in the United States in at least some Southern coastal areas this summer, as it typically passes from person to person via the bite of the Aedes aegyptimosquito, U.S. health officials have said.
The latest vision findings, published online May 25 in the journal Ophthalmology, add to a growing body of evidence about how Zika may affect children's eye development and vision, the researchers said.
It's not known if the virus itself causes eye problems or if the problems are a consequence of Zika-associated microcephaly.
"To my knowledge, the eye problems we found have not been associated with Zika virus before," said study senior author Dr. Darius Moshfeghi, a professor of ophthalmology at the Stanford University School of Medicine, in Stanford, Calif.
"The next step is to differentiate what findings are related to the Zika virus itself versus microcephaly caused by the virus, in order to better understand which infants will need screening," he said in a journal news release.
The researchers said all babies with microcephaly in geographic areas affected by Zika should be examined by an ophthalmologist, advice that echoes screening recommendations from the U.S. Centers for Disease Control and Prevention.
Such examinations "can contribute significantly to our understanding of the infection," the study authors wrote.