Cortical visual impairment caused by twin pregnancy.

PURPOSE: To report a possible relationship between twin pregnancy and cortical visual impairment.

METHODS: Three children who had been the products of twin pregnancies were identified as having cortical visual impairment. One child (Patient 2), a dizygotic twin, developed cortical visual impairment after a preterm birth. Two children (Patients 1 and 3), the products of monochorionic pregnancies, developed cortical visual impairment. All children were examined ophthalmologically and neurologically.

RESULTS: An evaluation of the gestations of these children indicates that twin pregnancy per se was probably etiologic in the development of cortical visual impairment. In Patient 2, twin pregnancy probably caused preterm birth and resulting cortical visual impairment. In Patients 1 and 3, twin-to-twin transfusion syndrome was the cause of cortical visual impairment. In Patient 1, fetal demise precipitated an acute twin-to-twin transfusion syndrome.

CONCLUSIONS: Children who show cortical visual impairment at or shortly after birth should be evaluated for the possibility of twin pregnancy. Twin pregnancy increases the risk of neurologic damage, including damage to the visual cortex, to optic radiations, or both.