Prenatal diagnosis of colobomatous microphthalmos

Optic nerve coloboma and microphthalmos with colobomatous cyst are rare congenital anomalies that are difficult to detect on prenatal ultrasonography and magnetic resonance imaging. Only four cases of optic nerve coloboma and two cases of microphthalmos with colobomatous cyst have been detected on prenatal imaging. The authors report a case of a fetus initially suspected to have retinoblastoma of the right eye on prenatal ultrasonography who was later diagnosed as having microphthalmos on fetal magnetic resonance imaging. Following delivery, she was noted to have microphthalmos with colobomatous cyst of the right eye and optic nerve coloboma of the left eye. The authors also review the prenatal ocular imaging findings of the differential diagnosis.