What are the causes of vision loss? What kind of process is this? You will find answers to these and other questions in the article. Loss of vision can occur either chronically (that is, over a long period of time) or acutely (that is, dramatically). The causes of vision loss are discussed below.
Vision loss ranges
A variety of scales exist to describe vision loss and its degrees. They are based on visual acuity. In the first edition, the National Health Organization in the ICD describes the difference as “blind legally” and “sighted legally”.
ICD-9, created in 1979, introduced the smallest continuous scale, which had three levels: standard vision, bad and blindness.
Acute loss of vision
Acute loss of vision can occur suddenly. It can be caused by ailments of the retina or optic nerve, clouding of refractive media, functional disorders or visual pathways. It may also be an accidental discovery of the fact of permanent loss of vision.
Turbidity of refractive media
The causes of vision loss are not always known. The clouding of refractive media in the eyes, such as the lens, cornea, vitreous body and anterior chamber, can lead to acute loss of vision, which is manifested in a decrease in visual acuity or blurred vision.
Although pupil reactions may be affected, these symptoms usually do not cause damage to the relative sensitivity of the pupils. Opacity appears due to hyphema, corneal edema, vitreous hemorrhage and cataracts.
Optic nerve damage
We continue to consider the causes of vision loss. Acute loss of vision can cause ailments that affect the optic nerve. Symptoms include a flaw in the afference of the pupils, an atypical pupil reflex when the optic nerves are affected on only one side. This may also occur due to the effects of a stroboscope.
The condition of the optic nerve depends on many ailments, including edema of its disk, papillitis, glaucoma, giant cell arteritis, neuritis and ischemic optic neuropathy.
Retinal Disorders
What other causes of sudden loss of vision exist? This disease can cause retinal defects. After all, if the retina is affected, then usually this is accompanied by a defect in the sensitivity of the pupils. Causes affecting or destroying the retina include:
- retinitis pigmentosa or occlusion of the vessels of the retina, the most important of which is occlusion of the median artery of the retina;
- retinal detachment;
- degenerative phenomena (for example, macular degeneration).
The 2013 tests brought the possibility of a complete retinal recovery.
Hypoxia
Everyone should know the reasons for the sharp loss of vision. It is known that the eyes are very sensitive to the localization of oxygen supply. Dimming of the vision (greyout or brownout) is accompanied by a loss of peripheral perception and may be the result of shock, low blood pressure, g-LOC (problems associated with aviation).
It can occur spontaneously, especially if a person is not completely healthy. The vision usually returns as soon as the causes localizing blood flow are eliminated.
Visual impairment
As you can see, there are many causes of sudden loss of vision. Among them are visual disturbances. What it is? These are any problems that interfere with the activity of the visual pathway. Very rarely, acute visual loss causes hemianopsia homonymous and, even less commonly, cortical blindness.
In addition, injuries can cause sudden loss of vision in both eyes.
Functional impairment
The term "functional disorder" is used today when the patient resorts to simulation and hysteria. This determines the doctor’s ability to detect the subjective skills of the patient (and thus find out whether the patient sees or not).
Nuances
In medical terms, vision loss is called amaurosis. You already know that it can be a consequence of ischemia or detachment of the retina, bilateral damage to the cortex of the eye, or destruction of the optic nerves. Patients with an acute developing illness require urgent treatment for vision loss and hospitalization.
At the same time, the information that the ambulance doctor can collect is important and helps to quickly make a diagnosis at the outpatient stage.
Loss of vision in one eye
What are the causes of sudden loss of vision in one eye? Such a defect usually appears as a result of damage to the optic nerve or retina and other structures of the eye. One of its common causes is a temporary circulatory disorder in the retina. As a rule, patients complain of a veil that suddenly appeared in front of the eye and often captures only a fraction of the field of vision.
Sometimes synchronized temporary weakness in the opposite limbs and a violation of sensitivity. This episode can last from two minutes to three hours.
In 90% of cases, the cause of vision loss is retinal artery embolism from an atherosclerotic ulcerated plaque in the carotid internal artery, aortic arch, or heart (often with atrial fibrillation or valve damage).
Much less often, a person loses vision due to a fall in blood pressure with severe stenosis of the carotid internal artery. Agree, there are a lot of reasons for the loss of vision in one eye.
If this happened suddenly, this may be a harbinger of a stroke, and a person should be actively examined immediately. Treatment for the loss of vision of this form is carried out using the continuous intake of aspirin (per day 100-300 mg) or indirect anticoagulants (with cardiogenic embolism).
Transient blindness with migraine
What are the causes of temporary loss of vision in one eye? In young people, transient blindness in one eye may appear due to retinal migraine. Loss of vision in this case is listed as a migraine aura that occurs shortly after the onset of a headache or precedes its onset.
However, even with a standard history, it is appropriate to exclude pathology of the heart and carotid arteries using special testing. A distinctive diagnosis is also performed with a visual aura in the form of a flickering migrating scotoma during an attack of a typical migraine. But the visual aura, as a rule, involves the left and / or right fields of vision in both eyes, and not one eye. In addition, when she closes her eyes, she remains visible in the dark.
Loss of vision with ischemic neuropathy
Ischemic anterior neuropathy of the optic nerve is caused by a deficiency of blood flow through the posterior ciliary artery, which supplies blood to the disk of this nerve. Clinically, it is expressed in a sudden loss of vision in one eye, which is not accompanied by pain in the eyeball. The diagnosis of vision loss can be confirmed by examining the fundus. Edema and hemorrhage in the area of the optic nerve disc should be revealed here.
Most often, it progresses in patients with diabetes mellitus and long-term arterial hypertension, often in patients with polycythemia or vasculitis. In 5% of cases (most often in patients over 65 years old), neuropathy is associated with temporal arthritis.
The treatment of this type of vision loss requires urgent corticosteroid therapy, which is necessary to prevent the loss of vision of the second eye. Diagnosis of temporal arteritis is simplified when detecting painful hardening, lack of pulsation of the temporal artery and will take rheumatic polymyalgia.
Less commonly, people lose their vision due to posterior ischemic neuropathy of the optic nerve. Usually it causes a combination of arterial hypotension and severe anemia, which may be the culprit of nerve infarction in the retrobulbar segment. Sometimes ischemic posterior neuropathy appears against the background of great blood loss during surgical interventions, trauma, and gastrointestinal bleeding. Transformations in the fundus are not detected here.
In hypertensive crisis, vision may suddenly fall due to ischemic swelling of the optic nerve disc or spasm of the retinal arteries. Too rapid a decrease in blood pressure can lead to an optic heart attack.
Loss of vision due to optic neuritis
Optic neuritis is an inflammatory demyelinating ailment that often involves the retrobulbar segment of the nerve (retrobulbar neuritis), so pathology cannot be detected during initial fundus testing.
In many patients, in addition to acute loss of vision, pain is noted in the eyeball, which intensifies with its movement. More often, vision loss progresses at a young age, can relapse, and is often the first demonstration of multiple sclerosis. The treatment for the loss of vision of this form is performed by the intravenous administration of impressive doses of "Methylprednisolone" (1 g per day for 3 days), which accelerates the regeneration.
What happens with toxic neuropathy?
In case of toxic neuropathy of the optic nerves, a sudden loss of vision in both eyes may occur. Toxic neuropathy can occur due to poisoning with carbon monoxide, methyl alcohol or antifreeze (ethylene glycol).
Smoother development of neuropathy of the optic nerves with an increase in atrophy without a stage of disc edema can be caused by some medications - Isoniazid, Amiodarone, Levomycetin (Chloramphenicol), Streptomycin, Digoxin, Penicillamine, Ciprofloxacin as well as arsenic, lead or thallium.
Increased intracranial pressure
Blindness can occur due to intracranial hypertension and the progression of congestive disks of the optic nerves (with brain tumors or intracranial benign hypertension). She is often preceded by short episodes of blurred vision in both or one eye, which appear during the transformation of the position of the body and last a couple of seconds or minutes.
Therapy consists in the introduction of "Methylprednisolone" (drip intravenously 250-500 mg) and urgent consultation of a neurosurgeon and an ophthalmologist.
Occipital cerebral infarction
Suddenly appearing blindness in both eyes may be a consequence of bilateral infarction of the occipital lobes (cortical blindness). It usually occurs as a result of prolonged arterial systemic hypotension or blockage of the basilar artery (usually as a result of embolism). Atherosclerotic plaques located in the vertebral arteries are usually the source of embolism.
Before loss of vision, vertebrobasilar insufficiency usually appears with bilateral or unilateral paresis or paresthesia, dysarthria, ataxia, dizziness, hemianopsia, double vision.
Unlike bilateral blindness, resulting from damage to the optic nerves, with cortical blindness, pupillary reactions remain intact. In some patients with cortical blindness, anosognosia progresses: such a patient claims that he does not have blindness, that he simply forgot his glasses or the room is dark.
Loss of vision in hysteria
Carefully study the causes of short-term loss of vision, and then you can avoid such incidents. The acute loss of vision may have a psychogenic character and be one of the manifestations of hysteria. As a rule, such patients (mostly young women) say that everything around them is plunged into darkness (patients with cortical organic blindness often cannot describe their visual sensations).
In the history of such hysterical symptoms are often found:
- Mutism.
- Pseudoparesis
- Hysterical seizures.
- Lump in the throat.
- Hysterical gait disorders.
Against the background of acute loss of vision, pupillary reactions are usually standard, there are no stem symptoms. Unlike those around, whose extreme concern and mandatory presence can serve as an additional diagnostic criterion, patients are often not alarmed, but rather calm, and sometimes even mysteriously smile (“indifference is magnanimous”).
Reasons for smooth vision loss
If you feel a decrease in vision and the constant fatigue of the eyeballs, this may be due to incorrect reading, lighting, or working at a computer. It is also possible that this is an age. But often the problems are much deeper. The reasons for the loss of vision (we do not take into account the computer, age and lighting here), there are the following:
- The most important cause of smooth vision loss is fatigue. If a person does not eat properly, does not sleep enough, has regular stresses, then the whole body suffers. Eyes will give out your frustrated condition in the first place. You yourself probably noticed that after a stormy night, your eyes are tired, painful and red. One hard working day is enough for many people to come home with a tired, extinct look.
- Another known cause of vision problems is bad habits. Many people know that people who abuse drugs, smoking and alcohol often have poor eyesight, which is a result of the direct effect of destructive substances on the vessels of the eyes. Limited blood supply makes the eye vessels fragile and weakens vision.
- Also, vision can gradually deteriorate due to the presence of various infectious and sexually transmitted diseases, in which nerves are destroyed. Such damage affects the entire body, including the nerve endings, which are responsible for vision.
- Toxins also affect visual acuity. Slags and other harmful substances with which a person pollutes his body appear due to an unfavorable environmental situation and malnutrition.
Treatment
The treatment of the disease of the secondary form caused by the disease consists in the treatment of the underlying disease. In order to prevent the appearance of various eye diseases and support vision, it is necessary to carry out prophylaxis in time. It is necessary to visit an ophthalmologist every year, who in the initial stages will reveal all conceivable pathologies.
You also need to adhere to simple rules - regularly give rest to the eyes, use good lighting, have the right position when reading and writing, do exercises for the eyes.
You can also consider drugs that contain a complex of vitamins. It can be:
- Retinol (Vitamin A). It affects the reproduction and growth of cells.
- "Tocopherol" (vitamin E). Prevents detachment of the eye retina.
- Ascorbic acid (vitamin C). Responsible for tissue regeneration, collagen synthesis and blood coagulation.
- Thiamine (Vitamin B1). Promotes standard intraocular pressure, among others.
On the shelves of pharmacies you can find a huge number of different drugs in order to be treated for visual impairment.
Temporary blindness and congenital
What other reasons for temporary loss of vision? There is such a thing as "snow blindness" - the defeat of transient blindness from bright light. This condition got its name after a large number of cases of loss of vision of an antispasmodic nature from the contemplation of bright sunlight and snowy expanses, which, as a rule, lasts from a couple of seconds to several minutes.
In the 21st century, genetic engineering has gone a long way, and now doctors can help patients with a diagnosis such as congenital blindness. Until recently, this disease was considered incurable.
Glaucoma
What is the main cause of vision loss in glaucoma? It is known that glaucoma is a group of ailments characterized by a progressive decrease in vision caused by an increase in pressure inside the eye above the tolerance for the optic nerve. Glaucoma develops for various reasons, but the development of this ailment leads to irreversible loss of vision due to atrophy of the optic nerve.
What is the prevention of glaucoma? People over the age of 50 must undergo a routine medical examination every year with an examination of the fundus and measurement of eye pressure (performed by the local ophthalmologist at the clinic). Take care of your eyes and be healthy!