This antibiotic helps keep babies from contracting eye infections.Erythromycin ophthalmic ointment is used to treat gonorrhea and Chlamydia infections, which may be transmitted during birth. It is administered prophylactically. Although it will prevent the newborn from becoming blind if the infant is born with these infections, there is not enough information in the answer to help the mother understand how the ointment prevents blindness. The antibiotic ointment is not administered to protect the newborn from bright lights. Newborns are in fact required by law to receive erythromycin ophthalmic ointment, but simply stating this does not explain why it is administered.