Infants with microcephaly, whose mothers reported Zika virus symptoms throughout their pregnancies, were linked with ocular abnormalities associated with impaired vision, a small study of Brazilian infants found.
Of the 29 infants examined, 10 of these children (34.5%) had ocular abnormalities, though some children had them in both eyes (abnormalities were discovered in 17 total eyes), reported Bruno de Paula Freitas, MD, of Hospital Geral Roberto Santos in Salvador, Brazil, and colleagues.
The most common abnormality observed was focal pigment mottling, as well as chorioretinal atrophy (the loss of the outer layers of the sensory retina), which was visible in 11 out of 17 of examined infant eyes (64.7%), they wrote in JAMA Ophthalmology.
Optic nerve abnormalities were found in 8 eyes (47.1%). In addition, one infant had bilateral iris coloboma (a defect causing a hole in the structure of the eye, which usually occurs before birth) in both eyes and lens subluxation (partial dislocation of the lens) in one eye. There were no infants with vasculitis or active uveitis. An accompanying editorial by Lee M. Jampol, MD, of Northwestern University, said that based on current information, clinicians in areas where Zika virus is present should perform ophthalmologic examinations on all babies with microcephaly, but stopped short of calling for routine screening.
"Because it is still unclear whether the eye lesions occur in the absence of microcephaly, it is premature to suggest ophthalmic screening of all babies born in epidemic areas," he wrote.
In the U.S., the CDC recommends ophthalmic evaluation, including a retinal examination, within the first month of life for infants with microcephaly whose mothers traveled to or resided in an area with Zika virus transmission during the course of their pregnancy. The organization continues to update their guidelines about Zika virus, as well as their guidance about how clinicians should treat pregnant women who may have been exposed.
Interestingly, none of these mothers reported conjunctivitis during pregnancy, contrary to a prior study from 2009 that suggested conjunctivitis was a frequent finding in Zika virus infection.
Overall, de Paula Freitas' team found that 23 of 29 (79.3%) mothers had suspected Zika virus symptoms throughout pregnancy. Of these, 21 women reported a rash, 13 reported fever, and 11 reported arthralgia or joint pain. The majority (18 women) reported these symptoms in the first trimester. Infants were included if their head circumference was less than 32 cm (the cutoff for microcephaly in Brazil) and 18 (62.1%) of included infants were female.
The authors note that advances in Zika virus testing are needed in order to confirm that ocular abnormalities were linked to Zika virus, as the retinal lesions in this sample may also resemble West Nile virus or toxoplasmosis retinochoroiditis.