The optic nerve is a bundle of nerves that carry vision information from the retina to the brain thus optic nerve atrophy is a breakdown of that nerve. Ultimately, the retina can not send the impulses to the brain and this can lead to a loss of central, peripheral, and color vision and potentially blindness if the underlying condition is not addressed. Optic nerve atrophy is not a disease of in of itself, but it is a sign of a more serious condition.
Causes of Optic Nerve Atrophy
The causes of optic neuropathy are numerous. Causes include but are not limited to glaucoma, a stroke of optic nerve (anterior ischemic optic neuropathy), a tumor pressing on the optic nerve, inflammation of the nerve due to multiple sclerosis or other autoimmune conditions, infections, nutritional deficiencies, hereditary conditions, congenital defects, or medications and local radiation treatment.
Diagnosis of Optic Nerve Atrophy
Initially, your eyes will be dilated and inspected with an ophthalmoscope (in instrument) to examine the optic nerve. If optic nerve atrophy is present, the optic nerve will look pale due to a lack of blood flow to the area. Depending on what they expect the cause to be, different tests from there will be used. Often, due to the extensive differential diagnosis, a myriad of exams and laboratory tests will be conducted. This may include the aforementioned vision tests, a MRI of the brain, and blood tests may be considered depending on the likelihood of each of the potential causes.
There is no specific treatment for optic nerve atrophy since it is a sign of another disease. Once the cause is determined, that underlying condition will be addressed. Depending on the condition, vision may return back to normal or continue to progress. During this time, it is important to have regular vision exams conducted in order to monitor changes and if any sudden vision changes occur, to see the ophthalmologist as soon as possible.
Although ocular and visual migraines are used interchangeably, they are different entities. If the symptoms occurs in both eyes it is more likely a visual migraine; whereas if it occurs in one eye it is more likely an ocular migraine; however, if there is sudden new onset of vision loss, you should seek medical care.
Ocular or Retinal Migraine
An ocular migraine is a rare condition and is also called a retinal migraine. It is thought to be due to reduced blood flow or spasms of the blood vessels of the retina (back of the eye). This leads to temporary vision loss or blindness of one of the eyes. The person experiences a blind spot which can become enlarged during the episode. Typically, the symptoms resolve within an hour from onset. This can be pain-less or can occur with or be followed by a migraine. Complications may include irreversible vision loss and the exact incidence of irreversible vision loss is unknown.
Visual Migraine or Migraine Aura
This is a much more common and is considered a more harmless condition. It is more commonly called a migraine aura and is characterized by temporary visual loss that lasts less than 30 minutes. It is thought to occur due to abnormal electrical activity in the cortex of the brain. This typically affects both eyes unlike the ocular migraine. Symptoms vary much more and may include flickering blind spot, flashing lights, wavy or zigzagged ring of colored light, or a blind spot that moves across the vision. A migraine headache may occur shortly there after or no migraine can occur.
Treatment is highly individualized depending on frequency of migraines; however, those with either ocular or visual migraines are recommended to receive medications to reduce incidence of migraines (migraine prophylactic medications). These medications may include anti-seizure medications or antidepressants. Additionally, they are recommended to avoid potential triggers of migraines, which may inclue bright light, stress, hormonal changes, nitrates, fasting, and wine among many others.
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