Optic Nerve Hypoplasia (ONH): Symptoms, Causes, Treatments, And More.
Last updated: August 6, 2021
Optic Nerve Hypoplasia (ONH) is a non-progressive, medical condition that arises from the underdevelopment of the eye’s optic nerve(s) before birth. The likely course of Optic Nerve Hypoplasia is variable, as many people are able to live relatively unaffected lives, but others can experience severe vision impairment with the inability to receive light in one eye (unilateral) or both (bilateral).
Visual perception arises from signals transmitted from optic nerves to the brain. Given that underdeveloped optic nerves reduce the ability to transmit signals, visual function is diminished for people experiencing ONH.
Although there is no cure for ONH, early detection is important and certain strategies and low vision devices such as eSight can help enhance vision to those affected.
For this article, we researched and gathered all the information you need for a well-rounded understanding of Optic Nerve Hypoplasia and what can be done to better live with this condition.
What is Optic Nerve Hypoplasia?
Optic Nerve Hypoplasia (ONH) is a non-progressive, congenital condition in which the optic nerve is underdeveloped in one eye (unilateral) or both (bilateral). It is characterized by short optic nerves and loss of the ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL).
Since you see things as your eyes receive impulses from the optic nerves, your vision function is diminished when optic nerves are underdeveloped, as in the case of ONH. Since Optic Nerve Hypoplasia is present from birth, it is one of the most prevalent causes of vision impairment and blindness in children, accounting for 15%-25% of severe visual loss in children.
Optic Nerve Hypoplasia can occur alone or in combination with other ocular abnormalities, such as nystagmus which is defined as involuntary, abnormal eye movements. When you have ONH, you may only receive a sliver of light in one or both eyes, and your level of disability can range from minor to severe.
ONH is rarely isolated and frequently occurs in conjunction with other functional and anatomic abnormalities of the central nervous system. It can be a part of the septo-optic dysplasia (de Morsier’s syndrome) syndrome, including a midline brain malformation and hypopituitarism.
Prevalence of Optic Nerve Hypoplasia:
The prevalence of ONH appears to be increasing with time.
- Researchers believe that ONH affects females and males at the same rate.
- The prevalence of this disease is approximately 1 in 10,000 children, according to the National Organization of Rare Diseases.
- ONH accounts for approximately 25% of vision loss in infants, according to a report from the Oman Journal of Ophthalmology.
- ONH was the third most common cause of any vision impairment (after cortical visual impairment and retinopathy of prematurity).
Related Conditions of Optic Nerve Hypoplasia
- In many cases, children with ONH are also diagnosed with autism.
- Midline anomalies of the brain are common, such as cerebral atrophy and septo optic dysplasia.
- There may be hormonal insufficiencies, for example in the pituitary and thyroid glands.
Septo Optic Dysplasia (SOP) vs Optic Nerve Hypoplasia (ONH)
Midline anomalies of the brain such as cerebral atrophy and De Morsier syndrome, commonly known as Septo-Optic Dysplasia (SOP) are commonly linked to Optic Nerve Hypoplasia. SOP is a rare congenital abnormality characterized by abnormal development of the optic disc, and absence of the septum pellucidum in the brain. It leads to intellectual disability, spasticity, and impaired sense of smell and taste.
Optic Nerve Hypoplasia and Autism
In many cases, children with ONH are also diagnosed with autism. Autism is a developmental disorder that affects communication and behaviour, and although it is difficult to accurately diagnose in children with ONH, studies have reported overlaps in traits and behaviors Autism is now commonly viewed as a spectrum of widespread developmental abnormalities known collectively as Autism Spectrum Disorders (ASDs) rather than a singular diagnosis.
Read more about ONH and Autism:
- In a 2010 study of 83 children with ONH and significant vision impairment (acuities below 6/30), Parr and colleagues reported that 37% had social, emotional, or psychological problems, repetitive or confined, and communicating challenges in behavior; of which 84% had a clinical diagnosis of autism.
- It is difficult to accurately diagnose Autism in children with ONH, but there is an overlap in traits and behaviors such as repetitive behavior and language, “sing-song” language tone, difficulty engaging in the give and take of interactions, obsessions, nonocular self-stimulatory behaviors, and hypersensitivity to certain sounds, textures, tastes, and smells.
- Neuro-radiographic abnormalities, gastrointestinal (GI) problems, sleep disturbances, and seizures are also shared by children with ONH and those with ASDs.
Other Related Conditions of Optic Nerve Hypoplasia:
- Endocrinopathy (disfunction of an endocrine gland) affects the majority of children with ONH causing hormonal insufficiency. In most instances, hormonal abnormalities are thought to be caused by hypothalamic dysfunction rather than pituitary gland dysgenesis. Hypopituitarism, occurring when a pituitary gland fails to produce one or more hormones, was found in 75% of children with ONH in a prospective study. The most prevalent deficiency was growth hormone (GH) insufficiency, followed by hypothyroidism, adrenocorticotropic hormone (ACTH) deficiency, and diabetes insipidus. Hormonal problems may appear later in a child’s life.
SIGNS AND SYMPTOMS
Symptoms, Signs, and Risks of Optic Nerve Hypoplasia
Vision Symptoms of Optic Nerve Hypoplasia
Visual impairment is the main symptom of Optic Nerve Hypoplasia. While Optic Nerve Hypoplasia is manifested at the time of birth, symptoms might not be evident until the infant reaches adolescence. Vision problems in one or both eyes is common. Nystagmus (involuntary eye movements) appears typically between the ages of one and three months, followed by eye misalignment or crossed eyes. Most children may see some improvement in their vision in the first few years of life.
ONH vision symptoms may include:
- Lack of visual detail and general blurring of vision
- Unaware of people or objects in the periphery
- Visual acuity ranging from having no perception of light to being near normal
- Lack of depth perception, leading to the inability to locate objects in space correctly
- Avoiding light by limiting outdoor activities (mild Photophobia)
Behavioral Symptoms of Optic Nerve Hypoplasia
Children may display some behavioral symptoms of ONH including:
- Experiencing delays in acquiring skills to coordinate their muscular and mental activity
- Squinting, lowering their head, or refusing to participate in outdoor activities to avoid light if they have photophobia
- Having very limited food preferences, and could exhibit excessive lip-smacking while eating
Causes of Optic Nerve Hypoplasia
The fundamental cause of Optic Nerve Hypoplasia is not yet understood, according to the National Organization of Rare Diseases, which noted that, “in most cases, the disorder appears to occur randomly for unknown reasons.” However, researchers do know that ONH is a congenital condition.
Potential Risk Factors
Although the cause of ONH is unknown, there are studies that have shown some risk factors affecting a low number of cases.
Maternal and Prenatal Risk Factors
According to a study published in PubMed, young maternal age, first parity, maternal smoking, preterm birth, and variables related to preterm birth were all risk factors for ONH. Optic Nerve Hypoplasia appears to be linked to a variety of other anomalies, including those of the central nervous system, as well as symptoms of prenatal development disruption.
Smoking, alcohol, recreational drugs, anti-depressants, anti-convulsants, anti-emetics, anti-fungal medicines, infertility therapy, and quinine have all been linked to prenatal exposure.
Genetic Risk Factors
Due to a clinical overlap with previously recognized central nervous system disorders, a causal relationship to ONH has been assigned to several genes and transcription factors. The identification of some gene mutations, some leading to lack of development of the forebrain, pituitary gland abnormalities, and ocular structures defects, can play an important role in diagnosis and medical care for those affected with ONH.Read more about Genetic causes of optic nerve hypoplasia.
Diagnosis of Optic Nerve Hypoplasia
Laboratory or radiographic tests cannot currently detect ONH. It can only be diagnosed through a comprehensive direct eye examination by an ophthalmologist.
For those suspected of having ONH, techniques such as Magnetic Resonance Imaging (MRI) or Optical Coherence Tomography (OCT) are used to examine the corpus callosum and optic nerves. Because various abnormalities can resemble the MRI findings of ONH, ONH may be suspected but not diagnosed based on MRI results. In addition, blood testing can identify abnormal cortisol and growth hormone deficiency levels which are confirmatory in the diagnosis of ONH.
Ophthalmoscopic confirmation of a small optic disc is required for the diagnosis of ONH. Direct ophthalmoscopy, using a handheld device to examine the eye, is the best method for diagnosing ONH in young children. A number of funduscopic findings help to confirm the diagnosis of ONH. The most important is a comparison of the disc’s area to the size of the central retinal arteries overlying it. ONH can be established by taking measurements of the optic disc from fundus pictures and comparing the diameter or area of the disc to various retinal landmarks. The horizontal disc diameter (DD) to the distance between the macular and the temporal margin of the disc is one technique (DM). With normal vision, the DD/DM ratio of optic nerves is considered to be larger than 0.35. The majority of individuals with DD/DM ratios less than 0.35 are considered to have ONH, while some people with DD/DM ratios of 0.30 to 0.35 have normal vision. Therefore, those with a smaller nerve head are more likely to have ONH.
Another feature of ONH is the presence of convoluted retinal arterioles, venules, or both. However, vessels that are unusually straight and have little branching may also be present. Children with primary growth hormone deficiency have non-branching vascular patterns. There may or may not be a hypopigmented halo surrounding the nerves, the so-called “double-ring sign” that implies a smaller optic nerve than a scleral canal. Measuring the width of the optic nerve head can be challenging, which makes mild dysfunction difficult to diagnose.
Small Optic Disc
One sign of having Optic Nerve Hypoplasia is an optic disc that is smaller than average. The optic disk is the part of the eye responsible for the “blind spot” where there are no light-detecting cells, because it is where retina nerve fibers meet to create the optic nerve, connecting from the back of the eye to the brain. An eye doctor can determine the size of a patient’s optic disc by investigating with an ophthalmoscope.
Corpus Callosum and Septum Pellucidum
In children with Optic Nerve Hypoplasia, abnormalities of the corpus callosum, such as hypoplasia and partial or total agenesis of the corpus callosum, are common neuro-radiographic findings. The most common type is Corpus Callosum Hypoplasia.
A report from the Children’s Hospital of Los Angeles indicates that patients with ONH sometimes lack a corpus callosum (or have an abnormal one), which connects the left and right sides of the brain. Or, patients may have a malformed septum pellucidum, which is a membrane that connects lateral ventricles in the brain.
Neither of these defects will affect the function of the brain, but they do sometimes occur with ONH.
The frequency of Corpus Callosum Hypoplasia in the general population is estimated to be 1.8-2.1 per 10,000, and it affects 2.3% of developmentally disabled people. Nearly half of individuals with Corpus Callosum Hypoplasia have other central nervous system abnormalities, such as non-midline defects (cortical heterotopias, schizencephaly, white matter hypoplasia, polymicrogyria) that are also related with ONH. On the other hand, ONH occurs in less than 10% of children with Corpus Callosum Hypoplasia.
Magnetic Resonance Imaging (MRI)
Magnetic Resonance Imaging (MRI) is common for people suspected of having ONH. In patients with unilateral disorders, an MRI of the orbit may reveal a variation in the optic nerve diameter.
Treatment Options for Optic Nerve Hypoplasia
There are no treatment options for ONH as optic nerves cannot be repaired once damaged. Early detection and support from an eye specialist may minimize the impact of vision loss and help to improve development in children. Although medical and surgical treatments do not exist, there are strategies and low vision devices that can change everyday life.
Strategies for Children with ONH
Children with ONH should have their vision checked at least once a year, and any refractive problems should be addressed once the visual acuity reaches a functional level.
- Encourage fine and gross motor activities to help them develop and learn aspects of depth perception, such as ball throwing, pouring, and stacking
- Minimize effects of light sensitivity through adjusting lighting levels and reducing surface glare
- Consider all underlying behavioral conditions when developing an education plan
- Consult professionals to help create a positive feeding experience for those with limited food preferences
Most children with ONH require physical, occupational, and/or speech treatment. The need for early intervention to treat the developmental deficiencies associated with ONH is crucial.
To overcome an aversion to certain textures of food, therapists should focus on early development of oral motor skills. Youngsters who are demonstrating autistic symptoms should be assessed by a neuropsychologist who specializes in autism evaluations as well as evaluations of visually impaired children.
If such abilities are lacking, the neuropsychologist should consult a visually impaired teacher to alter the evaluation method.
Incorporating discussion into song can help with delayed verbal communication.
Low doses of melatonin in the evening or soporific dosages at night can be used to treat children with disrupted sleep cycles. This could make retraining the circadian clock easier.
Low Vision Apps
Your smartphone can be a handy resource by installing low vision apps, and the operating system may already come with options for disabled individuals.
- LookTel Money Reader instantly recognizes currency and speaks the denomination, enabling people experiencing visual impairments or blindness to quickly and easily identify and count bills.
- TapTapSee is designed to help the blind and visually impaired identify objects they encounter in their daily lives. Simply double-tap the screen and take a photo of anything, at any angle. You’ll hear the app speak the identification back to you.
- Bright Focus Foundation offers a brief overview of apps for people with low vision.
- American Foundation for the Blind suggests various accessible apps specifically for Android devices.
Optic Nerve Hypoplasia Glasses | Award-Winning Assistive Tech
eSight eyewear is a valuable option for those diagnosed with ONH.
Clinically-validated, eSight eyewear is a great solution for those diagnosed with ONH.
The eSight is a non-surgical wearable solution that provides the brain with increased visual information to naturally compensate for gaps in the user’s field of view. eSight is a popular choice for many users living with ONH, such as Nick Roberts who received an eSight thanks to our fundraising platform, eMPOWER. With eSight, Nick was able to experience 20/20 vision for the first time in his life. Now, Nick uses the device to read fine-print books required for his criminal justice studies program, scan menus in restaurants, and watch his favourite hockey team, the Florida Panthers.
With a cutting edge camera, powerful software capabilities and high resolution screens, our FDA approved device takes visual acuity, mobility, comfort and ease of use to a new level. eSight is one of the only tech devices that boasts substantial mobility for its users while ensuring all-day comfort and is clinically validated to result in enhanced vision of up to 7 lines on a doctor’s eye chart.
As well, for those with ONH who experience photophobia, eSight lets users adjust both the brightness and contrast of the screens, proving to be well-suited for people with light sensitivity.
What is the ICD-10 code for ONH?
The ICD-10 code for Optic Nerve Hypoplasia is H47.032
Is ONH genetic?
It is unclear whether ONH is genetic in nature. The disorder has been noted, albeit rarely, within families with more than one affected child. However, in most cases, the disorder appears to present randomly.
How is Optic Nerve Hypoplasia diagnosed?
A comprehensive ophthalmologic examination is required to diagnose ONH. This can include the use of MRI and CT scans to evaluate the optic nerve and associated brain structures.
Can ONH be cured?
There is no cure for ONH, but timely intervention in children can minimize the impacts of vision loss. Those affected with ONH could still benefit from eyesight-enhancing eyewear such as eSight.
Is Optic Nerve Hypoplasia a disability?
ONH can be considered a disability, due to the vision loss imparted by the condition.
Can you see with Optic Nerve Hypoplasia?
Level of vision is case-dependent for those with ONH. Some people may have full vision in one eye, mildly impaired vision in both eyes, or no light perception in either eye.
Does ONH get worse over time? Is it progressive?
Generally, ONH is a stable condition that does not progress with age.
What are the symptoms of optic nerve damage?
Symptoms of optic nerve damage include limited and/or distorted vision, inflammation of the eye, and vision loss.
How rare is ONH?
The prevalence of ONH is an estimated 1 in 10,000 children, making it relatively rare.
Can Optic Nerve Hypoplasia cause blindness?
Yes, some people with ONH are completely or partially blind.
Do all mothers of children with ONH use drugs during their pregnancy?
No. While drugs may be associated with the development of ONH, they are not causal in nature and the disorder can develop spontaneously without drug use.
What test can be done for children with Optic Nerve Hypoplasia?
Children who are suspected of having ONH should consult with an ophthalmologist for appropriate testing. This may include MRI, CT scans, and bloodwork.
Can you drive with ONH?
Some people with less severe cases of ONH can drive, however, most people with the disorder are unable to drive safely due to vision impairment or loss.
Can glasses help Optic Nerve Hypoplasia?
New glasses technology has emerged that can drastically improve eyesight for people with Optic Nerve Hypoplasia.
For example, eSight has developed glasses equipped with a high-tech camera, high resolution displays, and intelligent algorithms, which has assisted people with vision impairment to regain their mobility and independence.
Community Resources and Support Groups
Feeling isolated is common when dealing with a medical condition such as ONH. You can improve the situation by finding support systems and sharing stories with others who are going through similar difficulties.
FB – Optic Nerve Hypoplasia and Septo Optic Dysplasia Support Group: supports parents, family members, and guardians of children who have ONH or SOD
FOCUS Families: provides information, education, and support to those affected by ONH and SOD worldwide
ONH Consulting: provides direct and personalized guidance, support and advocacy services to families of children and youth with ONH
One Small Voice Foundation: strives to give a voice to all children with ONHFamilyConnect: gives parents of visually impaired children a place to support each other, share stories and concerns, and link to local resources
Latest Research and Publications
New information about ONH is published every day.
- Genetic and Rare Diseases Information Center: GARD Information Specialists provide current, reliable, and easy to understand information about rare or genetic diseases in English or Spanish
- MAGIC Foundation: publishes brochures on a number of endocrine disorders written by globally recognized thought leaders and researchers on each topic
- National Federation of the Blind: creates and distributes several publications and audio reports to inform about the true nature of blindness and issues of interest to the blind
- Blind Children’s Center: sells a straight-forward, easy to understand booklet that shares educators’ and therapists’ observations and advice for parents of children with ONH
American Foundation for the Blind: provides publications with relevant and practical resources that support teaching, research, independent living, and the delivery of critical services for people with vision loss.