Optic neuritis
Optic neuritis is an inflammation of the optic nerve. As optic neuritis affects the ability to see, it is most frequently called an ophthalmology problem. Indeed, when an optic nerve is involved, it is almost always a symptom of the systemic disease. Optic neuritis can be most often seen as a complication of a multiple sclerosis. An eye doctor needs to get involved to manage the vision and inflammation of the optic disc. A neuro-ophthalmologist is a specialist who treats optic neuritis. The main symptom is sudden vision loss and pain in one eye that is worse with eye movement.
In this article:
- What is optic neuritis?
- Symptoms
- When to see a doctor
- Causes
- Optic neuritis in children
- Risk Factors
- How is optic neuritis diagnosed?
- Tests for Diagnosing Optic Neuritis
- Is it possible to prevent optic neuritis?
- What is the long-term outlook?
- References
What is optic neuritis?
Patients with acute demyelinating optic neuritis are typically healthy young adults and most patients present between 20 and 45 years of age. Optic neuritis is highest in populations located at higher latitudes (eg, Northern United States; Northern and Western Europe; New Zealand and Southern Australia) compared with geographic locations closer to the equator.
In the US, studies have estimated the yearly diagnosed cases as 5 to 6.4 per 100 000, with a prevalence of 115 per 100 000. Whites of Northern European descent develop this disease eight times more frequently than blacks and Asians.
Symptoms
Usually, the symptoms start rapidly with pain in the eye and vision loss. As a matter of fact, there are many other conditions that can be confused with an optic neuritis, such as:
- Ocular migraine
- Eye trauma
- Foreign body in the eye
- Eye infection (pink eye)
- Eye tumors
- Sinus infection
In some of the conditions even the vision can be affected. It is difficult to advise when exactly you need to see a doctor, but there are couple of hints you might have an optic neuritis:
- Sudden onset, not proceeded by a trauma or foreign body
- You have another diagnosis of systemic neurologic disease, such as multiple sclerosis, neurofibromatosis or neurosyphilis
- You have had optic neuritis in the past
- You are a young male of a white European descent
When to see a doctor
Any time you have significant eye pain which is associated with poor vision it is time to see a doctor. If the pain is too severe to handle, or there are other symptoms of distress (loss of consciousness, vomiting or any systemic neurologic symptoms – you should consider going to the closest emergency room or calling an emergency line.
Optic neuritis can affect children and teenagers who otherwise do not have any problems. It is important to take your child to the primary care doctor who will refer you to an ophthalmologist (if needed). Any type of vision loss in a child is a significant concern.
Causes
Multiple causes of optic nerve inflammation exist:
- autoimmunity,
- infection,
- granulomatous disease,
- paraneoplastic disorders,
- demyelination.
Finding out which type of an optic neuritis you have is crucial for initiation of a timely and appropriate treatment. Fast and correct treatment can prevent vision loss and blindness. In addition, understanding the cause of optic neuritis informs on visual prognosis, illuminates future health risks, and directs additional evaluations and treatments. Differentiating between various causes of optic neuritis, however, often requires a multifaceted evaluation that extends beyond a clinical history and neuro-ophthalmologic examination.
Visual field perimetry, optical coherence tomography (OCT), MRI, serologic testing, and CSF analysis may help to focus the differential diagnosis or identify an alternative diagnosis. Therefore, an initial overview of the clinical presentation, examination findings, evaluation, and treatment of the patient with optic neuritis is warranted.
Optic neuritis in children
In most reports of optic neuritis, most children were older than 12 years. It is important to note, however, that these studies have not defined puberty by anything other than age (no clinical signs o sexual development mentioned).
Recent studies in general confirm what was known before. A retrospective study of 59 children presenting with the first episode of PON (at ages 3.9–18.8 years) showed that 89% of patients recovered at least 20/40 visual acuity within 1 year. Only 2 patients had vision ≥20/200 in the worse eye at 1-year follow-up. Both of these patients developed multiple sclerosis (MS).
Visual acuity at presentation, sex, bilateral involvement, optic disc edema, and underlying diagnoses did not cause vision loss after recovery. All but 4 patients with unilateral optic neuritis and mild vision impairment were treated with steroids and/or intravenous immunoglobulin of plasma exchange. It is uncertain whether the visual outcome by underlying diagnosis was affected by treatment.
Risk Factors
Optic neuritis develops frequently as a complication of a systemic disease or inflammation. Here are couple of risk factors:
1. Multiple Sclerosis. Optic neuritis affects roughly 70% of patients with MS and is the presenting symptom in approximately 25% of individuals. Women are affected twice as often as men, and whites dominate the racial distribution. Optic neuritis is frequently unilateral and painful and progresses over 1 to 2 weeks; bilateral optic neuritis and severe vision loss (count fingers or worse) are uncommon.
2. Neurodegenerative systemic conditions. NMOSD is a central nervous system (CNS) inflammatory disorder that frequently involves the optic nerves and spinal cord. Serum autoantibodies against MOG (MOG-IgG) identify patients who develop isolated and recurrent optic neuritis. MOG-IgG-associated optic neuritis is slightly more common in females (57%), displays no distinct ethnic predilection, and is frequently affecting both eyes (37% to 44%).
3. Acute optic neuritis may occur in the background of systemic or neurologic immune disorders. Occasionally, optic neuritis may be the presenting symptom of a systemic immune process.
- Sjogren’s syndrome
- Lupus (SLE)
- Granulomatosis with polyangiitis (previously known as Wegener granulomatosis) is a multisystem small vessel granulomatous vasculitis that commonly presents with sinonasal, respiratory, and renal disease. Approximately 30% of patients with granulomatosis with polyangiitis are reported to have ocular involvement
4. Paraneoplastic optic neuritis is associated with an autoimmune response against collapsin response mediator protein. Small cell carcinoma is the most frequently associated tumor; however, prostate cancer, renal cell carcinoma, lung adenocarcinoma, and thymoma have been reported.
5. Infection. Direct infection of the optic nerve is a rare cause of optic nerve inflammation. Infectious optic neuritis, however, is important to identify as rapid initiation of appropriate antimicrobial, antiviral, antifungal, or antiprotozoal agents may be important for preventing further vision loss, facilitating visual recovery, or treating concurrent systemic or CNS disease. Optic neuritis occurring in conjunction with fever, meningitis, cranial nerve palsies, and encephalitis should always raise concern for an infectious cause. Optic neuritis with disc edema and cranial neuropathies should be investigated for Lyme disease in endemic areas. Syphilitic optic neuritis is often associated with ocular inflammation. Optic disc edema, when present, is usually prominent. A detailed social history identifying high-risk behavior for HIV should be performed in suspicious cases.
6. There are still situations when risk factors cannot be found. Autoimmune optic neuropathy, chronic relapsing inflammatory optic neuropathy, and relapsing isolated optic neuritis are terms used in the literature to describe cases of recurrent, seronegative optic neuritis.
How is optic neuritis diagnosed?
Visual field perimetry, optical coherence tomography (OCT), MRI, serologic testing, and CSF analysis may help to focus the differential diagnosis or identify an alternative diagnosis. Therefore, an initial overview of the clinical presentation, examination findings, evaluation, and treatment of the patient with optic neuritis is warranted.
The classic presentation of optic neuritis associated with multiple sclerosis is unilateral, moderate, painful vision loss with an afferent pupillary defect and normal fundus examination. Bilateral vision loss, lack of pain, and severe loss of vision should raise concern for an alternative inflammatory optic neuropathy.
Neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein (MOG)-IgG optic neuritis cause severe vision loss and are more frequently bilateral. MOG-IgG optic neuritis frequently causes significant optic disc edema.
Tests for Diagnosing Optic Neuritis
Visual evoked potential. This is a sensitive test of the axonal transmission along the optic nerve. An abnormal latency (delay) on visual evoked potential testing confirms the presence of an optic neuropathy. But visual evoked potential testing will not differentiate the cause of inflammation nor inform on visual prognosis. Visual evoked potentials, however, may prove useful in confirming subtle cases of optic neuritis. Furthermore, a significant increase in P100 latency without a drop in amplitude is consistent with a demyelinating optic neuropathy, while a drop in amplitude suggests concurrent axonal injury.
Visual field exam. Visual field defects due to optic neuritis vary considerably. Therefore, the pattern of visual field loss is not specific for any subtype of optic neuritis. Diffuse or central visual field loss is the most frequent pattern observed in acute idiopathic optic neuritis and MS optic neuritis; altitudinal field loss may be more frequent in NMOSD optic neuritis than MS optic neuritis.
Optic coherence tomography. OCT is a noninvasive imaging technology capable of identifying subtle optic nerve and retinal pathology. OCT frequently identifies peripapillary retinal nerve fiber layer thickening in acute optic neuritis that evolves into focal retinal nerve fiber layer and macular thinning. Unfortunately, initial studies have not identified any correlation between acute retinal nerve fiber layer changes and visual outcomes or treatment response. OCT angiography is a new adaptation of OCT technology that provides high-resolution information on retinal blood vessels and may provide novel diagnostic and prognostic information in patients with optic neuritis. OCT angiography reveals decreased vessel density in the peripapillary retina and macula following optic neuritis.
Magnetic resonance imaging. MRI is a very sensitive tool for the detection of optic neuritis. MRI of the orbits with fat suppression and gadolinium enhancement detects acute optic neuritis lesions in 95% of affected individuals within 20 days of vision loss; T2-weighted images with fat suppression and short tau inversion recovery (STIR) detect lesions in up to 89% of acute optic neuritis cases with abnormalities persisting for as long as 6 weeks in 92% of cases. In addition, the distribution and appearance of optic nerve, orbital, brain, and meningeal inflammation associated with acute optic neuritis may help to differentiate between autoimmune, infectious, and granulomatous inflammation
Is it possible to prevent optic neuritis?
If we knew what exactly causes optic neuritis in people, we could find the way to prevent it. It is not one of the common diseases, so we do not have sufficient research in preventive measures. Meanwhile, we know that immune system is definitely involved causing inflammation of the optic nerve.
As such, the recommendation for the healthy lifestyle is definitely in place here:
- eat organic bio food, balance nutrients and food components (fat, carbs and proteins)
- exercise daily with cardio
- spend time outdoors allowing skin to naturally absorb sunlight and produce vit D
What is the long-term outlook?
The recovery and further prognosis vary significantly because the systemic disease can determine eye condition.
If optic neuritis is a single case unrelated to other diseases, the prognosis is good with steroid treatment.
Because visual recovery is usually good regardless of treatment, at issue is the risk of developing neuroinflammatory or demyelinating disease, and whether or not vision loss can be minimalized in those cases that fail to recover.
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