Optic Nerve Hypoplasia (ONH)
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What Is Optic Nerve Hypoplasia (ONH)?
Optic nerve hypoplasia (ONH) is a condition present at birth, characterized by an underdeveloped or absent optic nerve (bundle of nerves that transmit messages between the eyes and the brain). The effects of optic nerve hypoplasia have a broad range dependent on the adequacy of visual messages sent from the eyes to the brain, from little or no visual impairment to near-total blindness. The condition may affect one or both eyes.
Infants and children with ONH may have accompanying hormone deficiencies, brain abnormalities, and nystagmus (involuntary darting of the eyes).
Vision loss is not progressive; in fact, vision may improve slightly over time, and nystagmus may decrease.
How Is Optic Nerve Hypoplasia Diagnosed?
Parents may notice a lack of eye contact and visual responsiveness and will have their child assessed by an ophthalmologist; alternatively, the child will visit an ophthalmologist for a routine eye exam. When the child’s eyes are dilated, the ophthalmologist will note that the optic nerve is small and/or pale in color. A diagnosis will be given.
Are There Treatments for Optic Nerve Hypoplasia?
At present, there is no treatment for condition of the optic nerve. However, if your child has a more severe visual impairment in one eye, the ophthalmologist may recommend patching (occluding) the better eye in order to encourage the weaker eye’s use.
If your child has accompanying hormone deficiencies, medication will be given to control the pituitary gland.
How Would You Describe the Eyesight of One with Optic Nerve Hypoplasia and How Will My Child Function with It?
While it is possible to have typical vision or total blindness with ONH, children and adults with ONH commonly experience poor visual acuity (blurriness) which is not correctable with glasses, peripheral field loss (“tunnel vision”) as well as sensitivity to bright light and glare (“photophobia”).
An individual with poor visual acuity may have difficulty recognizing faces and facial expressions as well as accessing near and detailed information. If this is the case, your child may benefit from increased room and task lighting; utilizing assistive technology to more easily write, read, use the computer, and access information; and to utilize techniques and additional accommodations to perform activities with limited vision.
An individual with loss of peripheral vision has some degree of “tunnel vision” making it difficult to gather comprehensive visual information in an environment; he or she will benefit from learning visual efficiency skills such as scanning an environment in an organized manner. Additionally, the individual is likely to bump into side-lying and low-lying obstacles; he or she should learn orientation and mobility (travel) techniques, such as the use of a cane, to avoid obstacles.
An individual with photophobia may benefit from specialized sunglasses (amber-tinted lenses), use of a brimmed hat while outdoors as well as shutting blinds while indoors if glare is present.
If your child is totally blind, he or she must be taught to complete tasks without the use of vision. Your child may be taught braille, screen-reading software to use the computer, and techniques for performing life skills and academic tasks from the teacher of students with visual impairments and orientation and mobility specialist.
Your child’s teacher of students with visual impairments should perform a functional vision assessment to determine how your child uses his or her vision in everyday life and a learning media assessment to determine which senses your child primarily uses to get information from the environment. These assessments, along with an orientation and mobility assessment conducted by a mobility specialist, will give the team information needed to make specific recommendations for your child to best access learning material and his or her environment.
Resources for Families of Children with Optic Nerve Hypoplasia