Scientists just discovered a disturbing new defect associated with the untreatable Zika virus

Scientists have found a disturbing new component to the birth defects associated with the Zika virus.

In one of the first studies published related to the recent Zika outbreak, researchers in Brazil documented the eye abnormalities in babies with a traditionally rare condition called microcephaly. Babies with the condition are born with abnormally small brains, which can be connected with other complications. It's not unusual for vision problems to be associated with microcephaly.

They found that in one-third of babies with microcephaly - after a presumed Zika infection before they were born - there was an additional eye abnormality that could threaten their vision.

Ten of the 29 babies observed had irregularities in one or both eyes, and about 80% of the mothers reported Zika-like symptoms during their pregnancy.

This led the researchers to conclude that Zika is linked to this eye problem, including damage to the retina, the layer at the back of the eye that's responsible that converts images into signals that are sent to the brain.

"We're very concerned about this," Lee Jampol, a professor of ophthalmology at Northwestern, told USA Today. "There hasn't been enough testing yet to know what these babies' vision is going to be."

In an accompanying editorial, Jampol and fellow Northwestern ophthalmologist Debra Goldstein advised that babies born with microcephaly in areas with Zika virus should have their eyes examined, though that recommendation didn't extend to babies in areas with Zika virus that don't have microcephaly. The study and editorial were published Tuesday in JAMA Ophthalmology.

For the most part, only about one in five people with Zika ever shows symptoms, which most commonly include fever, rash, joint pain, and red eyes, though there have been cases of a temporary neurological disorder called Guillain-Barre Syndrome associated with Zika.

It's Zika's connection to microcephaly that's particularly concerning. This connection has raised concerns about pregnant women contracting the virus. There are currently no vaccines nor treatments, though vaccines are in early development. The best way to prevent infection is to avoid being bitten by the mosquitoes that transmit the disease, by either avoiding travel to areas where the virus is being transmitted, or wearing long clothes and using mosquito repellent.