Optic neuritis: Symptoms, treatments for inflammation of the optic nerve

Optic neuritis

What is optic neuritis?

The optic neuritis is a neuropathy of the eye which is, as its name suggests, an inflammation of the optic nerve. The latter’s particular function is to transmit visual information from the eyes to the brain.

Optic neuritis affects central vision. Areas called “not seen”  (scotoma) appear in the field of vision. Contrasts and colors are difficult to distinguish, just like objects displayed in bright light. 

There are two types of optic neuritis:

  1. The “papillitis” which reach the anterior part of the optic nerve and are accompanied by papillary edema (infiltration of the optic papilla). It is also referred to as nerve papillitis or anterior inflammatory optic neuropathy. They result in a significant drop in visual acuity , a papilla with hemorrhages or exudates at the fundus.
  2. The retrobulbar optic neuritis (NORB) reflects inflammation of the optic nerve behind the eyeball, which is not accompanied by papilledema this time.

These phenomena can be reversible, but  can also progress to near-blindness .

Numbers: what is the frequency of neuritis?

According to medical literature, optic nerve neuritis is the main cause of acute vision loss in young and middle-aged adults. Its incidence is estimated between 1 and 5/100 000 people per year. This disorder more readily affects Caucasian and female patients.

In 15-20% of cases, optic nerve neuritis is the primary manifestation of multiple sclerosis (MS). Its prevalence varies between 40 and 50% in patients with MS and post-mortem studies report 100% of attacks in autopsies performed in patients of the latter group.

Optic neuritis: what are its symptoms?

The occurrence of optic neuritis can be accompanied by various symptoms:

Loss of vision

Optic neuritis interferes with the proper transmission of visual information from the eyes to the brain. This is what causes moderate or severe loss of visual acuity, unilateral or bilateral. Vision loss can increase in 1 or 2 days. The visual function of the affected eye (s) may vary from near normal acuity to complete blindness in the most severe cases.

Doctor Raynaud, ophthalmologist reminds us on this subject of an old adage according to which “in these cases, we say that the patient sees nothing and the doctor no longer has it, because the clinical examination seems normal”.

Visual impairment

Visual blurring and decreased contrast are not uncommon in optic nerve neuritis. Color vision may be particularly affected, but the person may not notice it. This visual impairment is very often accompanied by headaches.

Eye pain

Most people experience eye pain when moving their eyes.

Optic neuritis: what are its causes?

The origin of optic neuritis can be various:

Multiple sclerosis

Retrobulbar neuritis is one of the most common manifestations of multiple sclerosis (MS), an autoimmune disease affecting the central nervous system. In MS, the immune system attacks the myelin that surrounds and protects nerve fibers. This is the reason why MS is said to be a demyelinating disease .

Neuromyelitis optica

Another type of demyelinating disease, neuromyelitis optica affects the myelin sheath in the eyes and spinal cord.

Infectious diseases

Some of them can lead to optics neuritis. We find this type of condition if it is meningitis, viral encephalitis, tuberculosis, syphilis of sinusitis, or of Lyme disease. Locoregional infections in the tonsils or teeth can also degenerate into optic neuritis.

Other possible causes

  • A vasculitis (inflammation of blood vessels).
  • A vitamin deficiency of the B group.
  • The absorption of certain toxic substances such as lead, tobacco, arsenic and quinine which affect the optic nerve.
  • Certain cancerous metastases affecting the optic nerve.
  • Diabetes.
  • The atherosclerosis.
  • The anemia.
  • Of insect bites.
  • Certain antibiotics.
  • The literature also reports an association with vaccination against BCG, hepatitis, rabies virus, tetanus and rubella.

What are the risk factors?

Beyond the aforementioned causes, tobacco and alcohol poisoning is a major risk factor for optic neuritis.

Who are people at risk for optic neuritis?

There is a prevalence in adults aged between 20 and 40 years . It preferentially affects Caucasian populations and the female sex.

How long does an optic nerve neuritis last?

The duration of neuritis depends on the underlying cause. The majority of cases resolve spontaneously with a return of vision within 2 or 3 months of the onset of symptoms. However, some patients have repeated episodes of optics neuritis.

Is optic neuritis contagious?

This optical syndrome is not a contagious condition.

Who, when to consult in case of optic neuritis?

As soon as symptoms appear, it is recommended to consult your doctor. The latter can refer you to an ophthalmologist if necessary.

What are the complications of optic syndrome?

The major complication risk in optic neuritis is complete blindness.

Read Also: Why do my eyes hurt and what to do?

What tests and tests are necessary in case of optic neuritis?

The diagnosis of optic syndrome is primarily clinical. This disorder is suspected in the event of pain and loss of visual acuity, in particular in young subjects. 

What tests can diagnose optic neuritis?

Finally, an MRI (magnetic resonance imaging) is the reference examination in case of suspicion of optic neuritis. It is performed with injection of gadolinium and allows to highlight a hypertrophy of the optic nerve. MRI can also be used to diagnose MS, neuromyelitis optica or, more rarely, a tumor compressing the optic nerve.

Treatments

The main treatment for neuritis is to treat its cause . Early and appropriate treatment allows remission of the optic nerve.

In most cases, eye pain goes away on its own within a few days and visual problems improve. However, recovery is not always perfect. In a small minority of cases, vision continues to deteriorate over time. An intravenous anti-inflammatory treatment with corticosteroids is then generally prescribed.

Prevention

To date, there is no specific prevention for optic neuritis. However, it is recommended to regularly consult an ophthalmologist to assess visual capacity, and thus identify any deterioration as soon as possible.

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