Congenital nystagmus in two infants born from mothers exposed to methadone during pregnancy

BACKGROUND: Methadone is commonly prescribed as a substitute for illicit opioids. Use of methadone during pregnancy is associated with neonatal abstinence syndrome (NAS), reduced head circumference as well as a slight increase in neonatal mortality and morbidity. Less is known about the effects of methadone on the visual system. CASES: We report two Italian cases of nystagmus in infants born from mothers exposed to methadone during pregnancy. Ophthalmic or central disorders were excluded as a cause of nystagmus in both infants. The first case was followed at 3, 6 and 12 months while the second one was evaluated at 5 and 8 months. Both infants had normal neurological and cognitive development. Their first evaluation revealed different characteristics but both showed progressive improvement in ocular disorder, persistence of pendular horizontal nystagmus and nearly normal visual acuity. CONCLUSION: This report, the first description of Italian cases of nystagmus related to use of methadone during pregnancy, underlies the importance of a careful investigation of drug use in pregnancy in cases of unexplained congenital nystagmus.