Optic Neuritis – Symptoms and Causes

Overview

The optic nerve works like a communication cable connecting your eyes to your brain. It contains many nerve fibers covered with a protective coating called myelin.

When this nerve becomes inflamed, it can cause pain when you move your eyes and temporary vision loss, usually in one eye.

This inflammation often links to other conditions. It might be the first sign of multiple sclerosis (MS), a disease that damages nerves in the brain and optic nerve.

The inflammation can also happen with infections or immune system diseases like lupus. In rare cases, a condition called neuromyelitis optica causes inflammation in both the optic nerve and spinal cord.

Treatment Options

Most people recover their vision without any treatment after experiencing optic nerve inflammation. The healing happens naturally over time.

In some cases, doctors may recommend:

• Steroid medications to help speed up vision recovery.
• Regular eye exams to monitor progress.
• Additional testing if MS is suspected.

Many patients see improvement within a few weeks, though complete recovery may take several months. If you experience sudden vision changes or eye pain, seek medical attention promptly for proper diagnosis and care.

Symptoms

Optic neuritis typically affects just one eye. People with this condition may experience pain that gets worse when they move their eye. This pain sometimes feels like a dull ache behind the eye.

Vision loss in one eye is common. The loss usually develops over hours or days and gets better over several weeks to months. However, some people have permanent vision changes.

Other symptoms include:

• Side vision problems that can affect any part of the visual field.
• Color perception changes where colors appear less vibrant than normal.
• Flashing or flickering lights that some people see when moving their eyes.

Most people experience at least some temporary decrease in vision, though the severity varies from person to person. The symptoms typically develop rapidly rather than gradually.

When to See a Doctor

Contact your doctor if you notice any of these eye-related issues:

• New symptoms appear, such as pain in your eye or changes in vision.
• Existing symptoms get worse or don’t get better with treatment.
• Unusual symptoms develop, including:
  • Vision loss in both eyes
  • Seeing double
  • Numbness or weakness in your arms or legs (which might point to a nerve problem)

Causes

Optic neuritis develops when the immune system incorrectly attacks the myelin sheath covering the optic nerve.

This attack causes inflammation and damages the protective covering that helps electrical signals travel efficiently from the eye to the brain. When this process is disrupted, vision becomes affected.

While the exact cause remains unknown, several autoimmune conditions are strongly linked to optic neuritis:

Multiple Sclerosis (MS)

A disease where the immune system attacks nerve fiber coverings in the brain. People who experience optic neuritis have about a 50% lifetime risk of developing MS. This risk increases if brain lesions appear on an MRI scan.

Neuromyelitis Optica

This condition causes inflammation in both the optic nerve and spinal cord. Though similar to MS, it typically doesn’t affect brain nerves as often. However, neuromyelitis optica is generally more severe, with patients experiencing less complete recovery after attacks.

MOG Antibody Disease (MOGAD)

This condition can trigger inflammation in the optic nerve, spinal cord, or brain. Like MS and neuromyelitis optica, patients may experience repeated inflammatory attacks. Recovery from MOG antibody disorder is typically better than recovery from neuromyelitis optica.

Other potential causes include:

• Infections
  • Bacterial: Lyme disease, cat-scratch fever, syphilis
  • Viral: Measles, mumps, herpes
• Other Diseases
  • Sarcoidosis
  • Behcet’s disease
  • Lupus
• Toxins and Medications
  • Ethambutol (tuberculosis medication)
  • Methanol (found in antifreeze, paints, and solvents)

Risk Factors

Several factors may increase the chance of developing optic neuritis:

• Age: People between 20 and 40 years old face a higher risk.
• Gender: Women develop this condition more frequently than men.
• Ethnicity: White individuals have higher rates of occurrence.
• Genetics: Some inherited gene mutations might raise the risk of optic neuritis or multiple sclerosis.

These factors don’t guarantee someone will develop the condition, but they do indicate who might need more careful monitoring.

Possible Problems

Optic neuritis can lead to several issues:

• Nerve Damage: Most people experience some permanent damage to the optic nerve after an episode. However, this damage may not always cause lasting symptoms.
• Vision Changes: While most individuals recover normal or near-normal vision within months, some problems may remain. These problems include:
  • Partial loss of color perception
  • Persistent vision loss in some cases
• Treatment Side Effects: Steroids used to treat optic neuritis can cause:
  • Weakened immune system with increased infection risk
  • Mood swings
  • Weight increase

These complications vary from person to person, with many patients experiencing good recovery despite some remaining subtle vision differences.