Optic Nerve Hypoplasia / Septo-Optic Dysplasia

Optic Nerve Hypoplasia (ONH) is the under-development or absence of the optic nerve combined with possible brain and endocrine abnormalities. It is also known as Septo-Optic Dysplasia or DeMorsier's Syndrome. Now at epidemic proportions, ONH is the single leading cause of blindness and visual impairment in young children. A child diagnosed with ONH will undergo a number of evaluations and brain function tests. A neurologist can look at the brain structure through the use of CT (computerized tomography) or MRI (magnetic resonance imaging). After such tests, your doctor should be able to tell if there are major problems with brain structure. In some instances ONH includes the absence or abnormal development of the corpus callosum (a thick band of nerve fibers that connect the two hemispheres of the brain) and septum pellucidum (a thin membrane of connective tissue between the brain’s lateral ventricles). Abnormal development of the corpus callosum may or may not cause abnormal brain functions and the effects can range from mild to severe. Absence of the septum pellucidum does not affect brain functions.

Assessing the brain function of a child with poor vision can be difficult. Visually impaired children must be tested with different methods than non-visually impaired children. Be sure that your child is tested and treated by experienced specialists, which include pediatricians; psychologists; occupational, physical and speech therapists; and teachers of the visually impaired. The areas that can be affected involve gross and fine motor skills; intelligence, speech and interacting with people. In some people, brain abnormalities associated with ONH cause seizures.

The development of the pituitary gland, found at the base of the brain, can also be affected in children with ONH. The pituitary is the body’s master control gland, which makes and directs important hormones required for growth, energy control and sexual development. When a person doesn’t make hormones correctly, this is called hypopituitarism. The lack of these hormones can cause a great deal of problems for the children who are missing them.

Diagnosis
ONH is diagnosed by an ophthalmologist, who will use an ophthalmoscope to look inside the eye to determine if the front surface of the optic nerve appears smaller than normal. In addition, in some cases of ONH children will have a nystagmus, which is unusual eye movement. The eyes may seem to move around with no real pattern or purpose. This occurs because the eyes are not able to focus well enough to hold still.

Treatment
You will need to make sure your child is under the care of an endocrinologist, a doctor who specializes in gland problems. In addition, an ophthalmologist should monitor your child’s vision on an ongoing basis.

All of the endocrine conditions can be managed through daily medication routines. The medications are delivered by nose, mouth or injection. Even with close and careful monitoring, the endocrine deficiencies can be dangerous to those afflicted. Without careful monitoring, these conditions can be deadly.

Other Information

Optic Nerve Hypoplasia: A Guide for Parents (click to download PDF)
A general diagnostic overview of ONH.

Hipoplasia del Nervio Óptico: Guía Para Los Padres (click to download PDF)
Una descripción de diagnóstico general en español.

Childhood Blindness: What Are the Options? (click here)

Doctor: China's Stem-Cell Therapy for Kids is Risky (click here)

For information about participation in ONH research (click here).