Optic nerve hypoplasia and septo-optic-pituitary dysplasia

The presence of a small optic disc on funduscopy is prerequisite for the diagnosis of optic nerve hypoplasia (ONH). Visual acuity may be normal. However, amblyopia can occur in ONH. A relative afferent pupillary light defect indicates unilateral or asymmetrical ONH. Septo-optic-pituitary dysplasia (SOD) is diagnosed when ONH is associated with midline defects (e.g. hypopituitarism, small pituitary gland size, absent septum pellucidum, or abnormal corpus callosum). Olfactory bulbs/tracts agenesis or hypoplasia may occur with loss of smell. Pituitary function, neurological comorbidities (e.g. epilepsy, cerebral palsy), and psychiatric comorbidities (e.g. mood or anxiety disorders) should be evaluated regularly in patients with ONH/SOD. The risk of hypopituitarism continues until pubertal completion. Autopsy studies suggest that SOD is a clinical and not a neuropathological diagnosis. Children and especially infants/toddlers with SOD are at higher risk of acute hospital admissions and death than children without ONH/SOD. Respiratory tract illnesses are a common reason for their admission and is a frequent cause of their death. Healthcare professionals should be familiar with the comorbidities and complications associated with ONH/SOD, since they can be managed to reduce the mortality risk.