Optic nerve hypoplasia (ONH) is a congenital anomaly of the optic disc that might result in moderate to severe vision loss in children. ONH may occur as an isolated defect or in association with other ocular abnormalities, cranial abnormalities, or facial anomalies. Most of cases are sporadic, but autosomal dominant ONH have been identified. It is caused by mutations in PAX6 gene that encodes the transcription factor.
