What is Optic Nerve Hypoplasia?
Optic Nerve Hypoplasia refers to the underdevelopment of the optic nerve during pregnancy. When we see, light through the outside world enters the eye. It passes through the eye and enters the Optic Nerve. The Optic Nerve transmits the light from the eyes to the brain. It is our brain that processes the light that enters our eyes from the outside world and interprets it as images. This is what happens when we see. The Optic Nerve, in a real sense, is the telephone line that allows the eyes to communicate with the brain.
For people with Optic Nerve Hypoplasia (ONH), the Optic Nerve is either nonexistent or did not develop properly. Many people with ONH also have malformation (Dysplasia) or absence (agenesis) of other structures of the midline of the brain that are physically near the Optic Nerve. These might include:
Though we have no information about the numbers of children with ONH (incidents), studies have shown that ONH is a leading cause of childhood blindness and visual impairment in the United States. The numbers of children born with ONH is increasing dramatically. There is no known cause for ONH. Though there have been a few reports of siblings with ONH, there is no current evidence to suggest that ONH is a genetic condition. Studies of potential genetic factors and ONH are being carried out, however, and specific gene mutations have been suggested as potential causal factors.
Children with ONH can have abnormalities in the structure of the brain, its function, or both. These abnormalities can be minor and have little to no impact on a child’s functioning and development. In some children, however, these abnormalities can lead to developmental delays and other challenges. Many of these challenges include difficulties with sensory processing (discussed in more detail below), motor planning, intelligence and academic skills, speech and language, and higher order communication and social skills. Children who are most severely impacted can have smaller than normal brains as well as cysts (fluid-filled sacks) in their brains which sometimes have to be drained with an implanted surgical device called a shunt. Children and adults with ONH demonstrate a full range of intellectual functioning from mental retardation to high intelligence.
What are some major characteristics of ONH?
Optic Nerve Hypoplasia is associated with a host of unique characteristics that distinguish it from blindness or visual impairment due to other causes. Children with ONH can exhibit a wide range of vision, from fairly good visual acuity to total blindness. They may have rapid, involuntary eye movements. This is called Nystagmus. Since Nystagmus is involuntary, it is impossible for the person to control.
Many children with ONH have sensory processing dysfunction and Autistic behaviors and characteristics. Sensory processing is a term that describes how our bodies take in, manage, and respond to the information we receive from our senses. In people with sensory processing difficulties, this process doesn’t work as it should. Children with ONH who have sensory integration difficulties might be highly sensitive to certain textures, sights, sounds, smells, or other features of the environment. They might demonstrate a high pain tolerance and run into dangerous situations with reduced consideration for their safety. Extreme food preferences are very common. They might exhibit inappropriate and stereotyped behaviors, including hand-flapping, body-rocking, head-banging, biting or hitting parts of the body, and eye-pressing. While these behaviors can occur in other children who are blind or visually impaired, they can be much more intense and difficult to extinguish (get rid of) than in children without ONH. Distractibility, impulsivity, and trouble focusing and staying on task are also typical behaviors in children with ONH that have sensory integration dysfunction.
Many children with ONH demonstrate Autistic characteristics and some have behaviors that qualify them for a diagnosis on the Autism Spectrum by a psychologist or another professional qualified to diagnose behavioral disorders. A child with ONH might perseverate (talk excessively) on a specific and narrowly-defined area of interest, such as Rod Stuart or the sounds of telephone equipment. The fixations of many children with ONH revolve around music, which can be a powerful intrinsic motivator or even a means of communication with the outside world for some children.
Like some people with Autism and related conditions, some children with ONH also demonstrate special narrowly-defined skills which are unique to them. These are called “splinter” or sometimes “savant” skills. I, for example, can multiply large numbers in my head and recite the names of the first 107 elements of the Periodic Table in numerical order. Some others are profoundly gifted musically.
Since ONH can also affect adjacent structures in the brain such as the Hypothalamus, many children with ONH have additional and secondary medical complications. One of the most important of these involves the inability of the pituitary gland to function properly. This is called Hypopituitarism. The Pituitary gland is located at the base of the brain and controls the production of many critical hormones by other glands throughout the body. These include hormones that regulate metabolism, growth, and sexual development. For this reason, the Pituitary gland is sometimes called the body’s master gland.
One of the most important and potentially fatal complications of ONH is the inability of the adrenal gland to produce Cortisol. Cortisol is essential to the regulation of the body’s energy level, blood sugar, and proper functioning of the heart and lungs. The adrenal gland produces Cortisol several times a day when stimulated by a hormone from the Pituitary gland called ACTH, most notably during REM sleep. The pituitary gland also stimulates the adrenal gland to produce extra Cortisol during times of stress. This can include physical or emotional arousal, illness, surgery, or dehydration. If the Pituitary gland doesn’t function properly, it can’t produce ACTH and stimulate the adrenal gland to produce Cortisol. People who are unable to produce Cortisol must take oral medication called Cortef regularly and receive increased doses during times of physical or emotional stress, including arousal or excitement. If the body does not have enough Cortisol, it can lead to a condition known as an adrenal crisis. This can be lethal if not recognized and treated quickly with an injection of Cortisol directly into the muscles.
The pituitary gland also oversees the production of Growth Hormone, which not only ensures proper growth and bone density, but also plays a role in metabolism. A person who lacks growth hormone will have bones that are less developed than what would be typical for the person’s age. He /she might also have slow growth. When a doctor suspects that a person is deficient in growth hormone, he /she might do an X ray of the bones of the hand to check their density compared to others the person’s age or plot their growth on a “growth chart.” People who are deficient in growth hormone must receive regular injections of synthetic growth hormones until they stop growing or sometimes for the rest of their lives. Some adults with ONH have received growth hormone in order to facilitate their metabolism and normalize their blood sugar and energy level.
A person without enough Cortisol or growth hormone might have low blood sugar, called Hypoglycemia. Hypoglycemia can also lead to serious medical complications, including unconsciousness and seizures in severe cases.
If the pituitary gland doesn’t function properly, the thyroid gland might not receive the proper stimulation to produce enough thyroid hormone. Thyroid hormone is important to normal growth and metabolism. Lack of thyroid hormone can lead to irregular menstrual cycle (period), poor growth, slowing of mental and muscle functioning, coldness, brittle nails, and other symptoms. A doctor can easily measure thyroid hormone with a blood test. Those who don’t have enough thyroid hormone must take synthetic thyroid hormone in a pill.
Finally, if the pituitary gland is not functioning properly or at all, the person’s ability to produce hormones responsible for normal sexual development can be affected. The pituitary gland facilitates the production of the two major hormones that allow sexual development: follicle stimulating hormone (FSH) and leutinizing hormone (LH). Collectively, these hormones are responsible for the development of the male sex organ (penis) before birth. They also play a key role in bringing about puberty in boys and girls by signaling the production of testosterone by the testicles in boys and estrogen and progesterone in girls.
Boys missing these two hormones may be born with a smaller than normal penis. This is generally corrected by treatment with hormones in the first year of life. Since the hormones bring about sexual maturity in both boys and girls (puberty) as well as control the female menstrual cycle, a person without these hormones may have delayed sexual development, experience irregular or absent periods, and be unable to become pregnant or father a child. Fortunately, a person who is unable to produce sex hormones can have normal sexual development with hormone replacements.
How can a child with ONH develop fully and live a meaningful and productive life?
Children with ONH face a wide variety of challenges. They include blindness or visual impairment, medical complications such as Hypopituitarism, sensory integration difficulties, developmental delays, and seizure disorders. They can require a full range of support from families and professionals from many disciplines in order to successfully navigate school and develop into a productive and successful adult.
ONH is a condition that impacts every child differently. For example, one child with ONH might have only mild vision impairment with no pituitary abnormalities or sensory integration difficulties. Another child with the same condition, however, might have pituitary insufficiency requiring regular medication, sensory integration dysfunction, Autism, and total blindness. The following is only a sample of typical services and supports from health care, education, and other professionals that children with ONH might need to grow and live a meaningful and productive life.
Children with Hypopituitarism need diagnosis and treatment from a doctor that specializes in the glands, called an endocrinologist. When a child first receives a diagnosis of ONH, the endocrinologist can do any number of tests of different glands. For example, children with ONH commonly receive growth hormone and Cortisol stimulation tests to see if their bodies are making enough growth hormone or Cortisol. If they aren’t, they will need regular medication to replace the missing hormones. If the adrenal gland doesn’t produce enough Cortisol, the child will need to depend on synthetic Cortisol (called Cortef) to replace the missing Cortisol. Since the body uses extra Cortisol in times of stress, the child will need to take extra Cortisol while under stress. Situations where parents have had to give their children extra Cortisol have included surgeries, illness (even common illnesses such as the flu), and emotional stress. This latter situation can include times when the child is excited or emotionally aroused, such as a vacation or a trip to the amusement park. If a body doesn’t have enough Cortisol to function, it can lead to a condition called an adrenal crisis. Adrenal crisis is a potentially fatal condition if not treated immediately, and some children where Medic-Alert bracelets so that school personnel and paramedics will know what to do when their child has an adrenal crisis.
Children with ONH who are visually impaired can require specialized training in the alternative skills of blindness in addition to the regular school curriculum. This can include using Braille, large print, or recorded talking books, assistive devices such as computer software and closed-circuit TV to magnify print, and ways to do everyday tasks with limited or no vision.
There are several distinct types of professionals who train the blind. Trained vision teachers provide instruction in Braille and many other daily living skills at home, school, training facility for the blind, or in the community. There are a host of factors that can influence how a child with ONH is taught blindness and vision-related skills. For example, a child with sensory integration troubles might resist learning Braille, as Braille involves processing a high degree of tactile input and using that input to form letters and words in Braille. A child with sensory integration difficulties might physically resist attempts to teach him /her Braille or expose them to other new input through touch. When this happens, it is called tactile defensiveness. If a child is tactilely defensive, a parent or professional working with the child might opt to limit Braille instruction, particularly if the child has some usable vision. Tactile defensiveness can improve as the child matures and receives therapy to develop sensory integration.
Many children with ONH receive need occupational therapy (OT) services to improve sensory integration. He /she can receive OT services either through the school district or privately. It is important that the therapist be experienced in working with sensory integration and /or sensory defensiveness challenges, and not all physical or occupational therapists have this experience.
The therapist will provide structured activities to develop gross motor and fine motor coordination skills to help the child use information from the environment in a more efficient and organized way. Gross motor activities are those that involve use of large muscles and might include swinging, deep pressure massage, climbing, and jumping. Fine motor skills are those that involve use of small muscles such as those in the hands. Activities that improve fine motor coordination can include squeezing a therapy ball to stimulate the muscles of the hands and learning daily living skills that involve the hands, such as proper use of eating utensils and dressing.
Some children with ONH also receive training in age-appropriate social skills and interaction with others geared to those with Autism and related conditions, which is sometimes referred to as the Autism Spectrum. This training might include basic communication skills, age-appropriate interaction with peers, and managing perseverations /areas of special interest. A speech /language therapist (SLT) can provide this and other support to improve the child’s communication.
How can a Child with ONH receive these services?
Children with ONH often require services from many different types of organizations, including hospitals and health care providers, schools, non-profit and social service organizations, and organizations that provide specialized services to people who have blindness or visual impairment, Autism, or other disabilities.
Generally, children with ONH receive medical services through doctors and hospitals, though they might require medical intervention at home, school, or another setting. Some parents must navigate a very complicated patchwork quilt of funding agencies to receive these services.
Some parents can pay for medical care with private health insurance from an employer. However, many families require assistance from government agencies to ensure adequate treatment for their children.
Many children with complex medical conditions receive Supplemental Security Income (SSI), a monthly payment for those with low incomes and /or disabilities. In every state, SSI will allow a person to receive Medicaid services. Medicaid is a health insurance program for people with low-incomes and disabilities. In addition, some states offer programs that allow a child with a disability to receive services paid for by the state’s Medicaid program if they have a qualifying disability or have some other type of recognized special need. These special programs are often called “waiver programs” and can help a child with ONH who qualifies receive some needed services.
Finally, there are programs for children with special health care needs in each state for Children with Special Health Care needs (CSHCN). These are state agencies that provide health insurance, case management, and other services to children that have special medical conditions. Who qualifies for these services and what assistance he /she can receive varies from state to state.
In Ohio, for example, the Bureau of Children with Medical Handicaps (BCMH) is the designated state agency that offers these services to children and adolescents ages 0-21. BCMH has service coordinators that work with the child and family to ensure that the child is receiving all the medical care and assistance he /she needs. The agency also covers medication, inpatient and outpatient care, and some types of necessary medical equipment, such as blood-sugar meters as a “payer of last resort.” This means that the agency will pay for anything that Medicaid, private insurance, or other sources don’t cover. Service coordinators work in the child’s local community through the county (or in some cases the city) health department. The agency can refer families to other services, such as physical and occupational therapy as well. While having ONH alone doesn’t qualify a child for services, he /she may be covered if there is a secondary condition, particularly Hypopituitarism, that requires specialized medical care.
Children with ONH can receive Early Intervention (EI) services for infants and toddlers with disabilities. EI is a federally-funded program to ensure that children with disabilities are prepared to go to some type of school-based program, such as a regular school, school for the blind, or other specialized setting. Some children receive vision, orientation and mobility, and OT services through their state’s EI Programs.
When the child with ONH enters school, the local school district is required by law to ensure that he /she is in an appropriate school program. In general, children with ONH receive vision services (such as Braille instruction), speech, OT, orientation and mobility, as well as other supports to ensure that the child is successful at school and can reach his /her full potential.
As the child progresses through school, he /she may require additional support to transition to a successful and productive adulthood. These services might include continued specialized training in blindness or vision-related skills, vocational and career planning, and post-secondary or vocational training after high school.
The world that a child with ONH must navigate is difficult, complex, and often treacherous. ONH Consulting is your guide!