Optic nerve atrophy (ONA) is a condition resulting from optic nerve damage. The optic nerve lies at the retina's center, and its role is to carry information from the eye to the brain for processing. The nerve is made up of numerous small nerve fibers, which, when damaged through disease, inhibit information transfer to the brain, causing blurry vision.
Optic nerve damage can range from mild to severe, affecting peripheral, central, and color vision. The condition can develop gradually, presenting in one or both eyes. Usually, doctors do not consider ONA a disease but a sign or symptom of several disease processes.
Also Known As
- Optic neuropathy
The factors that trigger damage to the optic nerve form the various types of optic neuropathy, and they include:
- Optic nerve atrophy type 1
- Ischemic optic nerve dysfunction
- Toxic optic nerve dysfunction
- Optic nerve inflammation
- Nutritional optic nerve dysfunction
- Mitochondria optic nerve dysfunction
- Hereditary optic nerve dysfunction
Causes & Risk Factors
Causes of optic nerve damage range from eye trauma to various eye diseases. These include:
- Glaucoma - Glaucoma rarely occurs in children. However, among the few with the condition, it is usually identified before a child is six months old. If left untreated, aqueous humor in the eye continues to build up, causing optic nerve damage.
- Optic nerve inflammation - The inflammation attacks a covering in the nerve causing it to swell and eventually getting damaged.
- Nutrient deficiencies - Deficiencies in B vitamins are the cause of optic nerve damage. The vitamins facilitate cellular reactions and the production of adenosine triphosphate (ATP). The lack of these essential vitamins leads to the accumulation of toxic products within the cells, and a decrease in ATP production. When ATP becomes depleted, the nerve ceases proper functioning, and ultimately it gets damaged.
Other causes are genetic factors, toxins, certain medications, and brain tumors or stroke.
Signs & Symptoms
Despite there being various types of optic neuropathy, signs and symptoms are the same for all types. The common ones include:
- Reduced visual acuity
- Difficulties with discriminating contrast and identifying colors
- Neurological problems such as seizures, cortical visual impairment, and developmental delays or motor problems
- Decreased sensitivity in all visual fields
- A change in the optic disc which is only visible through an eye exam.
A pediatric ophthalmologist typically diagnoses ONA. If the doctor suspects that a child has the condition, s/he will first examine the child's eyes using an ophthalmoscope. S/he will then look at the optic disc, which would appear pale if the nerve is damaged.
The ophthalmologist may conduct other tests including, tests on visual acuity and color vision, pupil reactions to light, and MRI tests, where there are suspicions of a tumor or multiple sclerosis.
Damage to the optic nerve is irreversible. Therefore, treatment aims at addressing underlying conditions to prevent further damage. It may entail reducing heightened fluid pressure in the brain and spinal cord. Eyeglasses do not repair optic nerve damage, but doctors may prescribe them to treat refractive errors if they occur.
Parents and caregivers can ensure a child develops maximumly through the following ways:
- Allowing a child to rest when performing activities that involve utilizing the eyes
- Ensuring there is adequate lighting and contrast in the surrounding for a child to see clearly. For example, offering the child a light-colored toy against a dark environment.
- Observing the child to obtain information on how best s/he sees.
- Using real and familiar objects to stimulate visual attention, then changing a familiar object's feature as soon as the child can consistently recognize it.
- Describing present and future activities using words and touch. Additional senses enrich the learning process.
- Linking unfamiliar objects and settings to familiar ones when introducing them to the child.
A child's vision may severely decrease, so s/he may need assistance with learning and other activities. Through various visual agencies, the child can obtain resources and tools to aid in reading, writing, and walking.
Prognosis & Long-Term Outlook
The long-term outlook of the condition depends on the cause. A child's vision may be restored eventually if the cause is optic neuritis. Vision may not improve with other optic neuropathies.
Early diagnosis of glaucoma can lead to a successful treatment, which can slow down the progression of optic atrophy. Similarly, early detection of a tumor can prevent further damage to the optic nerve.
Prevention & Follow Up
Most causes of optic nerve damage cannot be averted. Others would require adopting measures such as regular eye examinations for glaucoma to monitor fluid pressure.