Optic Neuritis and Multiple Sclerosis, What You Should Know
Optic neuritis is a presenting condition in 20 percent of people who have multiple sclerosis. In fact, optic neuritis occurs in half of all individuals with MS at some time during their lives, so it’s important to understand this vision challenge.
Optic neuritis (also called demyelinating optic neuritis) is inflammatory demyelination of the optic nerve. Symptoms include vision loss (which can be permanent in some cases), seeing flashing or flickering lights, eye pain with eye movement, and loss of color vision. Usually the disease affects one eye only, but about 10 percent of patients have it in both eyes.
A common progression of optic neuritis is that vision worsens over about 10 to 14 days, after which visual loss stabilizes. Some visual recovery typically occurs within 30 days of onset, and spontaneous recovery of functional vision is usually excellent, with or without treatment. However, most patients still experience some problems with contrast sensitivity, light brightness, and color vision for as long as two years.
Optic neuritis and multiple sclerosis
The risk of eventual development of multiple sclerosis after an isolated attack of optic neuritis can be as high as 75 percent at 15 years. One reason optic neuritis is common in multiple sclerosis is that it involves damage to the optic nerve, which connects the eye to the brain. Since multiple sclerosis affects the brain, the optic nerve is often affected.
Optic neuritis is also common in MS because damage to the myelin in the brain from the disease can affect other areas that have an impact on the eye muscles. Once these sites are damaged, vision can be compromised.
Risk factors for optic neuritis include
- Being white
- Being a woman (twice the risk of men)
- Age 20 to 40 years
- A genetic predisposition, as certain genetic mutations may increase the chances of developing the vision problem
Diagnosing optic neuritis
Optic neuritis can be diagnosed by an ophthalmologist, who will perform several tests (e.g., ophthalmoscopy, which looks for swelling, pupillary light reaction test, visual response test) to make the determination. Use of magnetic resonance imaging (MRI) of the brain and orbits with gadolinium contrast can help confirm the diagnosis in most cases and can help evaluate the risk of subsequent MS.
In atypical cases, doctors may perform other tests. These can include a lumbar puncture, visual evoked potentials, and fluorescein angiography.
The prevalence of white matter abnormalities on brain MRI among people with optic neuritis has been reported to range from 23 percent to 75 percent. Individuals who have these abnormalities are at a greater risk of developing multiple sclerosis.
Recent study of optic neuritis
One of the most recent studies of optic neuritis and the eventual development of multiple sclerosis concerns children. The authors found that the presence of oligoclonal IgG bands in the cerebrospinal fluid in children who have demyelinating optic neuritis is a sign that multiple sclerosis will develop.
The study, which appeared in Nature Reviews Neurology, involved 357 children with isolated optic neuritis. Nearly 81 percent of those who had oligoclonal IgG bands in their cerebrospinal fluid eventually developed multiple sclerosis, compared with only 15.1 percent of children who did not have the bands. The authors noted that “cerebrospinal fluid analysis may supplement cMRI [magnetic resonance imaging] to determine the risk of MS in children with isolated ON [optic neuritis].”
Treatment of optic neuritis
Optic neuritis usually improves on its own, but treatment may speed up recovery. Treatment of optic neuritis includes oral or intravenous steroids, which can reduce inflammation. One approach involves three days of high-dose intravenous methylprednisolone followed by a tapering dose of oral prednisone.
Another treatment route is high-dose oral prednisone rather than the intravenous approach. Side effects of steroid treatment may include weight gain, stomach upset, mood swings, and insomnia.
Some experts suggest that patients who have optic neuritis and an abnormal MRI should be treated with disease-modifying drugs (interferon). Others suggest delaying treatment and repeating the MRI to get proof of multiple sclerosis before starting therapy, since it is expensive and associated with side effects. Choosing drug treatment is a highly individualized decision and should be discussed with a neurologist.
Atkins EJ. Optic neuritis and MS
CSF analysis could aid prediction of conversion from optic neuritis to multiple sclerosis in children. Nature Reviews Neurology 2015 Apr 28 online; DOI:10.1038/nrneurol.2015.69
Dalton CM et al. Spinal cord MRI in clinically isolated optic neuritis. Journal of Neurology, Neurosurgery, and Psychiatry 2003; 74(11): 1577
Uptodate. Optic neuritis pathophysiology, clinical features and diagnosis