Optic nerve hypoplasia: Symptoms, diagnosis and treatment
What is optic nerve hypoplasia?
Optic nerve hypoplasia (ONH) is a congenital disorder characterized by a child’s underdeveloped optic nerves. ONH can affect a child’s vision in one or both eyes. It often appears with other central nervous system (CNS) abnormalities that can impact the whole body.
Optic nerve hypoplasia is a congenital condition that develops during the first trimester of pregnancy. ONH affects about one in 10,000 children.
Babies born with optic nerve hypoplasia have an underdeveloped optic nerve, a nerve in the back of the eye that sends information from the eye to the brain. If the optic nerve is underdeveloped, it can inhibit the proper development of vision. The effect of ONH on vision can range from mild to severe.
Development of children with ONH may also be affected by issues with the brain, central nervous system and endocrine system.
ONH is also known by two other names:
ONH can result in developmental delays and a range of health problems related to deficiencies of key hormones. And, while optic nerve hypoplasia can lead to decreased vision, there are many cases where the presence of ONH has little to no negative effect on vision.
How does optic nerve hypoplasia affect vision?
The effects of ONH on vision vary based on the patient and can range from the inability to detect light to fully functioning vision. Other vision problems that may present in patients with ONH include:
Nystagmus – An involuntary rhythmic shaking of the eyes, nystagmus makes it hard to focus on an object. The presence of nystagmus typically reduces one's vision. Congenital nystagmus typically decreases as the child ages.
Strabismus – More commonly known as “crossed eyes,” strabismus prevents both eyes from working together properly. Strabismus often develops in an eye with reduced vision. If ONH results in reduced vision, the affected eye may “cross or turn.”
What causes optic nerve hypoplasia?
Doctors do not yet understand what causes optic nerve hypoplasia, but genetics may be a factor in some cases.
ONH may be linked with use of these substances during pregnancy:
LSD – A hallucinogen with a history of use as a street drug
Phenytoin – A common seizure control medication for epilepsy that carries risks for use during pregnancy
Quinine – A drug commonly used to treat malaria
Optic nerve hypoplasia has also been associated with fetal alcohol syndrome, a group of conditions caused by alcohol use during pregnancy. However, it's important to know that links are not the same as a cause. More research is needed to find the cause or causes of optic nerve hypoplasia.
Optic nerve hypoplasia symptoms
The detection of optic nerve hypoplasia may vary based on the child. The first signs parents may notice in infants may include:
Rapid, involuntary eye movements (nystagmus)
Signs of vision impairment in one or both eyes
Delays in development of some motor skills
Strabismus (crossed eyes)
Some ONH patients may also have problems with the pituitary gland, which produces and releases hormones. The specific symptoms will depend on the exact hormonal problems. Hormones from the pituitary gland play a major role in blood sugar regulation, growth, metabolism and other important bodily functions.
Optic nerve hypoplasia diagnosis
An eye doctor may be able to diagnose optic nerve hypoplasia with a comprehensive eye exam.
During the exam, the eye doctor will use drops to dilate the child's eyes before using a special magnifying lens to evaluate the optic nerve and retina. During this part of the exam, the eye doctor should be able to see a smaller-than-normal optic disc that may look pale or gray in color.
Based on the results of this exam, the child may also need further diagnostic tests such as:
MRI – Magnetic resonance imaging (MRI) is a type of imaging that can show the diameter of the optic nerve and detailed images of the brain.
OCT – Optical coherence tomography (OCT) is a painless type of imaging similar to an ultrasound that allows an eye doctor to get a detailed map of the optic nerve.
Blood work – Blood tests may be ordered to determine cortisol and growth hormone levels.
These procedures can help an eye doctor make a definitive diagnosis and get a better picture of the optic nerve, other structures in the eyes, and how the body as a whole is affected.
Optic nerve hypoplasia treatment
There are no medications or surgical treatments approved for treatment of optic nerve hypoplasia. However, a child with significant vision issues may benefit from working with a low vision specialist to get support and proper accommodations to help them comfortably complete school work and daily tasks. The specialist may recommend tools such as magnifiers and computer software to make daily tasks easier.
A patient who has optic nerve hypoplasia along with brain and hormone problems may need to get treatment from an experienced team of doctors that includes a pediatrician, an ophthalmologist or low vision optometrist, a neurologist and an endocrinologist. Depending on the specific case, treatment may include hormone replacement therapy.
The importance of eye exams
It's important to take your child for a comprehensive eye examination and to follow a regular schedule of eye doctor visits during childhood.
If you notice that your child may have vision issues, make an eye doctor appointment right away. Getting a prompt diagnosis for optic nerve hypoplasia will allow your child to get treatment for any existing vision issues, as well as any hormonal and neurological issues that may accompany the condition.
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Page published on Wednesday, December 15, 2021
Medically reviewed on Wednesday, December 8, 2021