Optic Neuritis: Causes, Symptoms & Treatment

Optic neuritis (technical term: neuritis nervi optici; also: retrobulbar neuritis) is an autoimmune inflammation of the optic nerve (optic nerve).

What is optic neuritis?

It often occurs as an early symptom of multiple sclerosis, but it also occurs without this underlying disease. After optic neuritis, some optic nerve atrophy may remain, with reduced visual acuity. In optic neuritis, there is autoimmune inflammation of the second cranial nerve (optic nerve). Initially, there is damage to the myelin sheaths, which electrically insulate the nerve and enable its high nerve conduction velocity. As the disease progresses, the actual nerve fibers (axons) are also affected by the inflammation and may perish.

Causes

Optic neuritis is still a poorly understood condition. In 70% of cases, its cause remains unexplained. In the remaining 30% of cases, optic neuritis is an early symptom of multiple sclerosis (MS). This is a so-called demyelinating disease in which myelin sheaths throughout the central nervous system (CNS) perish due to chronic inflammation. The etiology of MS is also not yet clear, despite major research efforts. Optic neuritis typically manifests between the ages of 18 and 45. The incidence is approximately 3 per 100,000 persons. Women are affected three to four times more often than men.

Symptoms, complaints, and signs

Optic neuritis can manifest itself through a variety of symptoms. Initially, the condition is noticeable by increasing eye pain that is localized behind the eyes and becomes more severe with eye movement or pressure. The pain is described as dull or throbbing, and the discomfort becomes more severe as the disease progresses. In addition, there are visual disturbances that can lead to complete blindness as the disease progresses. A blind spot develops in the center of the eye, which severely restricts the field of vision. In detail, the visual complaints are expressed by the fact that colors are perceived only attenuated and blurred into each other. If multiple sclerosis underlies the neuritis nervi optici, vision is impaired in the long term. In the meantime, vision may improve spontaneously, especially after acute episodes of the disease. Inflammation of the optic nerve also leads to headaches and dizziness, and occasionally nausea occurs. The actual inflammation causes general symptoms such as mild fever and malaise. If optic neuritis is treated early, symptoms resolve quickly. In the absence of treatment, chronic symptoms may develop and, in extreme cases, blindness of one or both eyes may result. Typically, only one eye is affected by neuritis nervi optici.

Diagnosis and course

The first symptom of optic neuritis is a rapid onset of visual acuity loss (visual loss). Patients experience blurred vision and sometimes mild pain or pressure sensations when moving the eyes. Headache and perception of flashes of light are common. A temporary worsening of the symptoms is also typical when the body temperature is elevated, e.g. in the sauna, in the bathtub or during sports. In extreme cases, complete blindness occurs. In 7% of cases, optic neuritis occurs bilaterally. Ophthalmologic examination of the fundus of the eye may be unremarkable; only in 35% of cases is a swollen optic disc visible. The diagnosis can be confirmed by magnetic resonance imaging (MRI), because demyelination foci can be detected on MRI. In addition to imaging techniques, cerebrospinal fluid (CSF) diagnostics provide evidence of the presence of multiple sclerosis. Electrophysiologic recordings can detect decreased nerve conduction velocity. Otherwise, optic neuritis is diagnosed based solely on its clinical symptoms and typical course. After rapid onset, inflammation usually persists for 1-2 weeks and then shows spontaneous remission. After 5 weeks, no improvement is expected. The extent of damage left behind depends on the extent to which the inflammation had already affected the optic nerve axons. While myelin sheaths can regenerate, axons are usually irreparable.95% of those affected regain visual acuity of at least 0.5 after healing, and 70% even regain visual acuity of at least 1.0 after surviving optic neuritis

.
Complications

The most dangerous complication of optic neuritis is complete blindness of the patient. In general, vision deteriorates rapidly when the optic nerves are inflamed. This increases the risk of accidents and falls in everyday life and at work. If the inflammation spreads to other parts of the body, infections in the nasopharynx, middle ear infections, and rarely skin irritations with itching, swelling, and redness may occur. Further complications depend on the cause of the inflammation. If multiple sclerosis underlies the symptoms, loss of vision is inevitable. Papillitis also results in visual loss, although it is usually less severe. Retrobulbar neuritis sometimes results in severe eye pain and temporary visual complaints. Treatment of optic neuritis also carries risks. Side effects such as swelling and gastrointestinal discomfort may occur as part of cortisone therapy. After taking antibiotics and antivirals, various symptoms may occur – including headache, sore throat, muscle and limb pain, skin redness and itching, and allergic reactions. Prolonged use of these drugs results in permanent damage to the kidneys, liver and heart.

When should you see a doctor?

Optic neuritis should always be examined and treated by a doctor. Only proper medical treatment can rule out further complications that could prevent healing. Therefore, a doctor should be consulted at the first signs and symptoms of optic neuritis. A doctor should be consulted if the affected person suffers from pain in the eyes. In most cases, this pain increases when the person moves his eyes or when the pressure on the eyes increases. Sudden visual complaints are also an indication of optic neuritis and must also be examined by a doctor if they persist over a long period of time without any particular reason. Many people affected by optic neuritis also suffer from fever, headaches and also nausea. If optic neuritis is not treated, it can also lead to blindness in the worst case. The disease can be treated relatively well by an ophthalmologist.

Treatment and therapy

Usually, optic neuritis resolves spontaneously even without medical intervention. Drug therapy with high-dose steroids can shorten the duration of optic neuritis, but studies have shown that this does not improve the final outcome, so patients do not retain better visual acuity than without treatment. Therefore, in discussion with the patient, the disease shortening must be carefully weighed against the side effects of steroid therapy. If at least two foci of demyelination are seen on MRI, administration of high-dose steroids should be offered in any case to delay MS neumanifestations. In case of a so-called atypical optic neuritis that does not show improvement even after 4 weeks, an infectious background must be considered. Antibiotics and/or steroids may help in this case. If the optic neuritis is due to multiple sclerosis, the underlying disease must of course be treated. This is not curable, but can be delayed and alleviated.

Prevention

Because neither optic neuritis nor the multiple sclerosis that often underlies it are fully understood, it is also unknown how to prevent this disease. However, non-MS-related optic neuritis is thought to be triggered by chronic intoxication with alcohol, tobacco, or quinine, various infectious diseases, and arterial hypotension, among others. Thus, to prevent optic neuritis, these risk factors should be avoided.

Follow-up

Optic neuritis must be completely cured. Follow-up care by the treating ophthalmologist ensures that the condition has been appropriately cured. First, a patient interview takes place. Here it is clarified whether the patient has complaints and whether the prescribed medication causes side effects. Depending on the findings, the doctor can take further measures.The aim of the medical history is to obtain as complete an overview as possible of the patient’s state of health. During the physical examination, the affected optic nerve is examined by means of visual diagnostics and, if necessary, further imaging procedures are performed. Typical symptoms such as impaired vision, but also sensory disturbances, must be clarified by the physician. An eye test may be considered for this purpose. Follow-up care is usually provided by the ophthalmologist who has already treated the optic neuritis. If complications arise during follow-up, other specialists may need to be consulted. For example, chronic disease may indicate a viral condition, which must be clarified and treated by an internist. In the case of other concomitant symptoms, neurologists or ENT physicians may be involved in the treatment. Follow-up care is based on the severity of the inflammation and symptoms.

Here’s what you can do yourself

Optic neuritis affects the quality of life enormously, as patients suddenly perceive reduced vision and additionally suffer from pain in the eye area. In their own interest, affected persons should help to ensure that the disease heals as quickly as possible. Otherwise, long-term damage to the sense of sight is possible. First of all, the medication prescribed by the doctor should be taken regularly. In the event of side effects, contact a medical professional immediately or go to an emergency practice. Even in the absence of complications, it is advisable to attend medical check-ups. This allows the doctor to determine the status of the healing process and, if necessary, adjust the dose of prescribed medication. In addition to taking the medical agents, rest and sparing play an essential role in speeding up the healing process. If possible, patients with optic neuritis should stay at home and remain on bed rest. Rest is not only important for the immune system, but above all for the sense of sight. Under no circumstances should patients look at screens such as cell phones or computers. In addition, the eye must be protected from irritating influences such as wind, pungent food vapors, heat, cold and bright light. After consultation with the attending physician, an eye patch or sleep mask may be useful to give the diseased eyes sufficient rest.