Optic neuritis
Diseases of the eye and diseases of the optic nerve are different pathologies. If the optic nerve suffers, then the process of transmission of the nerve impulse to the brain is disrupted. Neuritis can develop in people who have not previously had any vision problems. Pathology progresses quickly, and the acute period of the disease also quickly passes.
Content:
- Anatomy of the eye and optic nerve
- Neuritis reasons
- Symptoms of neuritis
- Diagnostics
- Differences between toxic neuropathy and neuritis
- Treatment of optic neuritis
- Prevention
Anatomy of the eye and optic nerve
In order for a person to see, light must fall on the receptors of his optic nerve, which is reflected from various objects. Optic nerve receptors are represented by cones and rods. However, before reaching them, the light rays pass through several structures of the eyeball.
These structures include:
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Conjunctiva. It is the thinnest film that covers the outside of the eyelids and the eyeball. It is not of great importance in terms of the transmission of light rays, but if this membrane becomes inflamed, then the pathological reaction from it can pass to the optic nerve.
- Cornea. This is a transparent plate that has a slightly curved shape. It is filled with liquid. Behind the cornea is the iris, which is ring-shaped. The pupil is located inside the iris. The iris has the ability to expand and contract. It depends on how much light passes through it.
- Lens. It can change its shape thanks to the ciliary muscle. The lens allows you to clearly see objects at different distances.
- The vitreous humor is a jelly-like structure that is responsible for the refraction of light rays.
- The retina contains the very rods and cones. The rods are responsible for twilight vision, and the cones are responsible for color perception. The retina is the initial section of the optic nerve. It creates momentum and transfers it further.
All structures of the eye are fed from the vessels that are located behind the retina. Pathologies of those parts of the eye that conduct light develop slowly, a person loses vision at the terminal stages. The neuritis has a fast course. The visual function suffers first of all during its manifestation.
Neuritis reasons
By itself, optic neuritis does not develop. It is always accompanied by some kind of infectious disease.
Therefore, it is necessary to clarify with the patient whether he recently suffered from such diseases as:
- Iritis (damage to the iris).
- Iridocyclitis (damage to the ciliary body and iris).
- Choroiditis (damage to the choroid).
- Keratitis (damage to the cornea).
- Conjunctivitis (damage to the outer eye membranes).
- Osteomyelitis or periostitis, which is characterized by infection of the bones of the orbit against the background of a previous injury.
- Frontitis, sinusitis, sphenoiditis, which are accompanied by inflammation of the sinuses.
- Tonsillitis.
- Chronic infections of a bacterial nature: diphtheria, neurosyphilis, typhus, gonorrhea, etc.
- Infectious brain damage: encephalitis, meningitis, arachnoiditis.
- Inflammatory processes in the oral cavity: periodontitis, caries, etc.
Sometimes optic neuritis develops after suffering a cold or flu. The first symptoms of the disease will appear as early as 4-7 days after suffering a cold.
Symptoms of neuritis
Neuritis develops unexpectedly for a person. Its manifestations may vary. Sometimes the disease is expressed in eye pain, and sometimes in visual impairment.
Experts distinguish between 2 forms of pathology:
- Retrobulbar neuritis, when the visual pathway suffers after leaving the eyeball.
- Intrabulbar neuritis, when inflammation is concentrated on the initial segment of the nerve, but within the eye.
Most often, neuritis affects only one eye.
Intrabulbar neuritis symptoms
Intrabulbar neuritis has an acute onset. Its first symptoms appear and intensify in 1-2 days. The stronger the damage to the nerve, the brighter the manifestations of pathology.
The main symptoms of the disorder:
- Scotomas. Blind spots appear in the person's field of vision. Most often they are located in the center of the eye. So, the patient sees with the affected eye all objects, except for those that are located in a certain area, for example, right in front of him.
- Myopia. Visual acuity falls in every 2 patients, but insignificantly, by 0.5-2 diopters. As the neuritis progresses, vision may be completely lost. Sometimes the pathology is reversible and sometimes irreversible. It all depends on whether the treatment was started on time.
- Deterioration of twilight vision. Normally, a person begins to distinguish objects in the dark 40-60 seconds after turning off the light. With developing neuritis, the eye adapts no earlier than after 3 minutes.
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Deterioration of color perception. A person may stop seeing certain colors. Sometimes colored spots begin to appear in the field of view.
Intrabulbar neuritis lasts 3-6 weeks. During this period, the person's vision will either be restored, or the person will be completely blind. In order for the outcome of the disease to be as favorable as possible, you need to see a doctor as soon as possible.
Symptoms of the retrobulbar form
Retrobulbar neuritis develops less frequently than intrabulbar neuritis. The nerve is located in the cranial cavity, so the infection can spread along its outer surface or along the inner surface. It is worse for a person if the entire optic nerve suffers.
| Type of neuritis | Place of concentration of infection | Main manifestations |
| Axial | In the center of the optic nerve |
|
| Peripheral | On the outer nerve fibers |
|
| Transversal | The whole nerve suffers | Symptoms include all of the above symptoms characteristic of axial and peripheral nerve damage. |
Diagnostics
To clarify the diagnosis, the doctor will refer the patient to undergo the following tests:
- Ophthalmoscopy. In a dark room, the doctor examines the fundus of the patient. For this, he uses a magnifying lens. This method allows you to assess the condition of the initial section of the optic nerve. If a person has neuritis, then he will have a red color. The disc swells, pinpoint hemorrhages may be visible on it.
- Fluorescence angiography. In this case, a drug is injected into a person's vein, which illuminates the vessels of the fundus. Then the doctor examines them using a fundus camera. This is an expensive study that requires the use of special equipment. It provides information about the condition of the optic nerve as a whole.
These methods will not give information about retrobulbar neuritis, since changes in the disc occur only at 5 weeks of development of the disease. Therefore, the diagnosis is made solely on the basis of patient complaints.
Differences between toxic neuropathy and neuritis
Neuritis and toxic neuropathy have similar symptoms, but they need to be treated in different ways. To choose the right therapeutic regimen, the doctor must correctly diagnose.
To do this, he needs to take into account the following points:
Consideration of the cause of the development of the disease. Neuritis always develops against the background of a viral or microbial infection. Neuropathy is a consequence of methyl alcohol poisoning or develops after taking large amounts of alcohol.
Sometimes the following causes lead to toxic neuropathy:
- Intoxication of the body with salts of heavy metals.
- Drug overdose. In this regard, NSAIDs, antibiotics, cardiac glycosides are dangerous.
- Poisoning with phenol-formaldehyde resins.
- With neuropathy, two eyes suffer, and with neuritis, one.
- With neuropathy, the iris muscle stops working, so the pupil remains dilated even when exposed to light.
- Ophthalmoscopy does not provide any information about the disease if the patient develops toxic neuropathy, as the nerve is destroyed after it leaves the eyeball.
- The therapy for neuritis does not affect vision function. This is the reason for the revision of the diagnosis.
Given these features, neuritis can be distinguished from toxic neuropathy. Treatment of neuropathy should be based on the elimination of the factor that led to its development. It is important to remove intoxication from the body. Then they stimulate the work of the optic nerve, for which they are prescribed drugs such as: Trental, Actovegin, Neuromidin, etc.
Often, toxic neuropathy leads to irreversible visual impairment, and treatment only improves the general well-being of a person.
Treatment of optic neuritis
To cope with visual neuritis, you need to influence the infection that provoked it. With the viral form of the disease, antiviral drugs (Amiksin) are prescribed, with a bacterial infection - antibiotics.
It is not always possible to accurately determine the pathogenic flora that provoked inflammation of the optic nerve, therefore, all patients are prescribed broad-spectrum antibiotics (Amoxiclav, Ceftriaxone).
| Drug group | Purpose of treatment | How to apply? | Drug name |
| Glucocorticosteroids | Reducing nerve swelling, eliminating nerve damage | With retrobulbar neuritis, the drug is injected with a special syringe into the tissue of the eye. With intrabulbar neuritis, the drug is taken orally. | Dexamethasone, Hydrocortisone, Methylprednisolone. |
| Detoxification drugs | They put a dropper with them | Gemodez, Reopolyglyukin. | |
| Vitamins | Improving metabolic processes, stimulating the transmission of nerve impulses. | Administered intramuscularly in the form of injections, if treatment is carried out in a hospital. On an outpatient basis, vitamins are prescribed for oral administration. | PP (nicotinic acid), B1 (thiamine), B6 (pyridoxine). Combined drug - Neurobion. |
| Preparations for improving microcirculation | Improving nutrition of nerve fibers | The drugs are prescribed after the main treatment, when the patient has a decrease in visual function. | Trental, Nicergoline, Actovegin. |
To improve nerve conduction, Nivalin or Neuromidin is prescribed. If, after the completion of treatment, the patient's vision has not been restored, then physiotherapy is prescribed to him. Most often, the patient is shown the passage of magnetotherapy, electrotherapy. Laser therapy has proven itself well.
Prevention
In order to prevent the development of neuritis, efforts must be made to prevent any infectious diseases. This is especially true for eye infections.
If the treatment of optic neuritis is started on time, then it is possible to prevent the development of such serious complications as loss of vision and blindness. To correctly diagnose and choose the right therapy, you need to contact an ophthalmologist.
Author of the article: Sokov Andrey Vladimirovich | Neurologist
Education: In 2005 completed an internship at the IM Sechenov First Moscow State Medical University and received a diploma in Neurology. In 2009, completed postgraduate studies in the specialty "Nervous diseases".
