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Glossary of Useful Terms

Listed below or available for download are some useful terms relating to Optic Nerve Hypoplasia along with their definitions and significance. These terms are used frequently within the ONH community and we hope this list can serve as a helpful resource.

Ableism – Discrimination and social prejudice against people with disabilities and/or people who are perceived to be disabled.  Ableism characterizes people as defined by their disabilities and inferior to the non-disabled. 

Absence Seizures (Petit Mal Seizures) – A type of seizure that involves brief, sudden lapses in attention. These seizures are more common in children than in adults.  Many children outgrow them, but some children develop other types of seizures. 

ACTH – Adrenocorticotropic Hormone – A pituitary hormone that tells the adrenal gland to make cortisol.

ACTH Stimulation Test – A medical test usually requested and interpreted by endocrinologists to assess the functioning of the adrenal glands’ stress response by measuring the adrenal response to adrenocorticotropic hormone or another corticotropic agent such as tetracosactide or alsactide. 

Addison’s Disease (Adrenal Insufficiency) – A disorder in which the adrenal glands don’t produce enough hormones. 

ADH – Anti-Diuretic Hormone – A pituitary hormone which keeps water in the body by controlling the amount of urine that is made. 

Adolescence – The period following the onset of puberty during which a young person develops from a child into an adult. 

Adrenal Glands – Two glands that sit on top of the kidneys and make several hormones, including cortisol.

Advocacy – Any action that speaks in favor of, recommends, argues for a cause, supports or defends, or pleads on the behalf of others. 

AFB – American Federation for the Blind – A national nonprofit that 

Amblyopia – Also known as lazy eye.  Decreased eyesight due to abnormal visual development.  Amblyopia occurs in early childhood.  When nerve pathways between the brain and an eye are not properly stimulated, the brain favors the other eye. 

Atonic Seizures (Drop Seizures) – A type of seizure that causes sudden loss of muscle strength.  The sudden lack of muscle strength, or tone, can cause the person to fall to the ground.  The person usually remains conscious and may not always fall.

Axon – Another name for nerve fibers. 

BIP – Behavior Intervention Plan – A written improvement plan created for a student based on the outcome of the functional behavior assessment. 

Bone Age – The degree of maturation of a child’s bones.  As a person grows from fetal life through childhood, puberty, and finishes growth as a young adult, the bones of the skeleton change in size and shape.  These changes can be seen by x-ray techniques.  

Convulsion – A strong spasm or series of twitches of the face, body, arms or legs. 

Corpus Callosum – The large nerve fiber bundle that connects the left and right sides of the brain. 

Cortisol – A hormone bade by the adrenal glands after activation by the pituitary hormone, ACTH.  Cortisol is needed to survive physical stress; maintain normal fluid, electrolyte, and blood sugar levels; and to maintain an energy supply. 

CT Scan – Computerized Tomography – A scan that combines a series of x-ray images taken from different angles around your body and uses computer processing to create cross-sectional images of the bones, blood vessels, and soft tissues inside your body.  CT scan images provide more detailed information than plain x-rays do. 

Cyst – An abnormal, usually noncancerous, growth filled with liquid or a semisolid substance, sometimes causing pain

DDAVP – Desmopressin – A medicine that is used when a child does not make enough ADH. 

DeMorsier’s Syndrome – A syndrome in children with Optic Nerve Hypoplasia who have problems with the formation of the septum pellucidum. 

Early Intervention – The system of services that helps babies and toddlers (up to 3) with developmental delays or disabilities. 

Early Start – The program in California that provides early intervention services to eligible infants and toddlers (up to their third birthday) who have a developmental delay. 

Endocrinologist – A specially trained doctor who is qualified to diagnose and treat hormone-related diseases and conditions.  

Epilepsy – A disorder in which nerve cell activity in the brain is disturbed, causing seizures.

Equality – Each individual or group of people is given the same resources or opportunities. 

Equity – Recognizes that each person has different circumstances and allocates the exact resources and opportunities needed to reach an equal outcome. 

Estrogen – The hormones which promote the development and maintenance of female characteristics of the body.  

Estropia – A type of strabismus in which one or both eyes turn inward. 

FAPE – Free and Appropriate Public Education – An educational entitlement of all students in the United States who are identified as having a disability, guaranteed by the Rehabilitation Act of 1973 and the individuals with Disabilities Act. 

FBA – Functional Behavior Assessment – An ongoing process of collecting information with a goal of identifying the environmental variables that control a problem or target behavior. 

Fine Motor Skills – The coordination of small muscles in movement with the eyes, usually involving the synchronization of hands and fingers. 

FSH – Follicle Stimulating Hormone – A hormone made by the pituitary gland.  In women, it causes the development of eggs and the release of estrogen.  In men, it helps produce sperm. 

Glucometer – A machine that is used to test blood sugar levels.

Gonadotropins – Two hormones (FSH and LH) which are normally produced by the pituitary gland.  These hormones stimulate the ovaries to produce a follicle which contains an egg and to release an egg from the ovary. 

Gross Motor Skills – The skills involving the ability to move arms, legs, and larger muscles (crawl, walk, run, climb, etc.)

Growth Hormone – A pituitary hormone that stimulates growth, cell reproduction, and cell regeneration. 

Growth Hormone Stimulation Test – The test that measures the ability of the pituitary gland to make growth hormone. 

Hormones – The body’s chemical messengers.  They travel in your bloodstream to tissues or organs.  They work slowly, over time, and affect many different processes, including growth and development, metabolism, sexual function, reproduction, and mood. 

Hypoglycemia – An abnormally small amount of glucose (sugar) in the blood. 

Hypopituitarism – A condition in which the pituitary gland does not make needed hormones.

Hypothyroidism – A condition in which the thyroid gland does not produce enough thyroid hormone. 

IDEA – Individuals with Disability Education Act – A piece of American legislation that ensures students with a disability are provided with a Free Appropriate Public Education that is tailored to their individual needs.  

IEP – Individualized Education Plan or Program – This is the plan to provide special education services to a student through the LEA. 

IFSP – Individual Family Service Plan – Plan to provide developmental services to a child through early intervention. 

IGF-1 and IGBPs – Growth factors that can be measured in the blood to screen for growth hormone deficiency. 

LEA – Local Education Agency – The school district where the student lives. 

Legal Blindness – A term used by the government to define central visual acuity 20/200 or less in the better eye with best correction, or widest diameter of visual field subtending an angle of no greater than 20 degrees.

LH – Luteinizing Hormone – A hormone that causes the release of sex hormones. 

Low Vision – Uncorrectable vision loss that interferes with daily activities.

LRE – Least Restrictive Environment – A statute under IDEA that states, to the maximum extent appropriate, children with disabilities are educated with children who are not disabled, and special classes, separate schooling, or other removal of children with disabilities from the regular education environment occurs only when the nature or severity of the disability is such that the education in regular classes with the use of supplementary aids and services cannot be achieved satisfactorily. 

Metabolism – The process by which substances needed for life are made and broken down. 

Moderate Visual Impairment – Snellen visual acuity of 20/70 to 20/160.

MRI – Magnetic Resonance Imaging – A medical imaging technique used in radiology to form pictures of the anatomy and physiological processes of the body. 

Neurologist – A specialist in the diagnosis and treatment of the disorders of the brain and spinal cord. 

NFB – National Federation of the Blind – The oldest and largest nationwide organization of blind Americans.  Through their network of blind members, they coordinate many programs, services, and resources to defend the rights of blind Americans, provide information and support to blind children and adults, and build a community that creates a future full of opportunities. 

Nystagmus – Rapid, involuntary to-and-fro shaking movements of the eyes. 

OD – Right eye.

ONH – Optic Nerve Hypoplasia – A congenital disorder characterized by underdevelopment (hypoplasia) of the optic nerves.  The optic nerves transmit impulses from the nerve-rich membranes lining the retina of the eye to the brain.  

Ophthalmologist – A medical doctor specializing in the diseases of the eye. 

Optic Disc – The front surface of the optic nerve that can be seen inside the eye with special instruments. 

OS – Left eye. 

OU – Both eyes. 

Panhypopituitarism – A condition in which the production and secretion of all hormones by the pituitary gland is reduced. 

Pituitary Gland – The “master” gland that sits under the brain and makes hormones, most of which activate other glands to make hormones. 

Profound Visual Impairment – Snellen visual acuity of 20/500 to 20/1000 OR visual field of 10 degrees or less. 

Progesterone – A female hormone that makes the uterus ready to accept a fertilized egg. 

Prolactin – A hormone made by the pituitary gland. 

Psychologist – An expert in assessing overall development, including thinking, speaking, memory, reasoning skills, learning, socialization and school achievement.  A psychologist can also help to understand and cope with different feelings related to illnesses, hospitalization, and treatment as well as help a child manage inappropriate behaviors. 

Puberty – The stage of growth when the reproductive organs start to work, the person matures and develops adult sexual characteristics. 

Radiologist – A medical doctor trained in the use of x-rays and other imaging. 

Septum Pellucidum – A thin wall of brain tissue which divides the ventricles. 

Severe Visual Impairment – Snellen visual acuity of 20/200 to 20/400 OR visual field of 20 degrees or less. 

Social Worker – A professional who works with children and their families to help them understand and adjust to hospitalizations and long-term illness.  The social worker provides counseling, help in getting financial assistance, and information about community resources. 

SOD – Septo Optic Dysplasia – A disorder of early brain development.  Although its signs and symptoms vary, this condition is traditionally defined by three characteristic features: underdevelopment (hypoplasia) of the optic nerves, abnormal formation of structures along the midline of the brain, and pituitary hypoplasia. 

SSI – Supplemental Security Insurance – Federal program which gives money to low income families to help care for children with disabilities.  

Strabismus – Disorder in which the eyes don’t look in exactly the same direction at the same time.  This can be caused by nerve injury or disfunction of the muscles controlling the eye. 

Tonic-Clonic Seizures (Grand Mal Seizures) – A type of seizure that involves a loss of consciousness and violent muscle contractions. 

Visual Acuity – A number that indicates the sharpness or clarity of vision.  A visual acuity measurement of 20/70 means that a person with 20/70 vision who is 20 feet from an eye chart sees what a person with unimpaired (or 20/20) vision can see from 70 feet away.

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