In perinatal infection, the primary manifestation is infection of the eye (neonatal conjunctivitis or ophthalmia neonatorum) when the newborn is exposed to "N. gonorrhoeae" in the birth canal. The eye infection can lead to corneal scarring or perforation, ultimately resulting in blindness. If the newborn is exposed during birth, conjunctivitis occurs within 2–5 days after birth and is severe. Gonococcal ophthalmia neonatorum, once common in newborns, is prevented by the application of erythromycin (antibiotic) gel to the eyes of babies at birth as a public health measure. Silver nitrate is no longer used in the United States.