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. Vision loss can occur either chronically (i.e. over a long period of time) or acutely (i.e. abruptly). The causes of vision loss will be discussed below.
Ranges of loss of vision
There are various scales to describe vision loss and its degrees. They are based on visual acuity. In the first edition, the National He alth Organization in the ICD characterizes the distinction as "legally blind" and "legally sighted".
ICD-9, created in 1979, introduced the smallest continuous scale that had three levels: standard vision, poor vision and blindness.
Acute loss of vision
Acute loss of vision can come on suddenly. It can be caused by ailments of the retina or optic nerve, clouding of the refractive media, functional disorders, or disturbances in the visual pathways. It may also be unintentional.discovery of the fact of permanent loss of vision.
Turbidity of refractive media
The causes of vision loss are not always known. Cloudiness of the refractive media in the eye, such as the lens, cornea, vitreous body, and anterior chamber, can lead to acute loss of vision, which manifests as reduced or blurred vision.
Although pupillary reactions may be affected, these symptoms do not usually cause damage to the relative sensitivity of the pupils. Opacity appears due to hyphema, corneal edema, vitreous hemorrhage and cataracts.
Optical Nerve Damage
We continue to consider the causes of loss of vision. Acute loss of vision can be caused by diseases that affect the optic nerve. Symptoms include a pupillary afferent defect, an atypical pupillary reflex when the optic nerves are affected on only one side. This may also occur due to the effect of the strobe light.
The condition of the optic nerve depends on many ailments, including swelling of its disc, papillitis, glaucoma, giant cell arteritis, optic neuritis and ischemic neuropathy of the optic nerve.
Retinal ailments
What other causes of sudden vision loss are there? 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 that affect or destroy retinal activity include:
- retinitis pigmentosa or retinal vascular occlusion,the most important of which is occlusion of the median retinal artery;
- retinal detachment;
- degenerative phenomena (eg macular degeneration).
Testing in 2013 brought the possibility of complete retinal repair closer.
Hypoxia
Everyone should know the causes of sudden loss of vision. It is known that the eyes are very sensitive to the localization of oxygen supply. Vision blackout (greyout or brownout) is accompanied by loss of peripheral perception and may result from shock, low blood pressure, g-LOC (aviation related problems).
It can also occur spontaneously, especially if a person is not completely he althy. Vision usually returns as soon as the causes that localize the flow of blood are eliminated.
Violation of visual paths
As you can see, there are many reasons for sudden vision loss. Among them are disorders of the visual pathways. What it is? These are any problems that disrupt the activity of the visual pathway. Very rarely acute visual loss is caused by homonymous hemianopia and, even more rarely, by cortical blindness.
In addition, sudden loss of vision in both eyes can be caused by injuries.
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 patient's subjective skills (and thus determine whether the patient sees or not).
Nuances
In medical language, loss of vision is called amaurosis. You already know that shemay result from ischemia or retinal detachment, bilateral damage to the cortex of the eyes, or destruction of the optic nerves. Patients with acutely developing disease require immediate vision loss treatment and hospitalization.
At the same time, the information that the emergency doctor manages to collect is important and helps to quickly make a diagnosis at the outpatient stage.
Loss of vision in one eye
What causes 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 frequent causes is a temporary disorder of blood circulation in the retina. As a rule, patients complain of a veil that suddenly appeared before the eye and often captures only a fraction of the field of vision.
Sometimes, temporary weakness in opposite limbs and impaired sensitivity are noted simultaneously. This episode can run from two minutes to three hours.
Retinal artery embolism from an atherosclerotic ulcerative plaque in the carotid internal artery, aortic arch, or from the heart (often with atrial fibrillation or valvular damage) is the cause of vision loss in 90% of cases.
Much less often, a person loses vision due to a drop in blood pressure with severe stenosis of the internal carotid artery. Agree, there are a huge number of reasons for loss of vision in one eye.
If this happens suddenly, it may be a harbinger of a stroke, and the person should be actively examined immediately. Treatment of vision loss of this form is carried out with the help of continuous intake of aspirin (100-300 mg per day) or indirect anticoagulants (for cardiogenic embolism).
Migraine transient blindness
What are the causes of temporary loss of vision in one eye? In young people, transient blindness in one eye may occur due to retinal migraine. Loss of vision in this case is listed as a migraine aura, which occurs shortly after the onset of a headache or precedes its attack.
However, even with a standard history, it is appropriate to rule out pathology of the heart and carotid arteries with specific testing. The differential diagnosis is also performed with a visual aura in the form of a flickering migratory scotoma in a typical migraine attack. But the visual aura usually involves the left and/or right visual fields in both eyes rather than one eye. In addition, even when you close your eyes, it remains visible in the dark.
Vision loss due to ischemic neuropathy
Ischemic anterior ophthalmic neuropathy is caused by a lack 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. Here, edema and hemorrhage in the area of the disk of the optic nerve should be revealed.
Most often it progresses in patients with diabetes mellitus and long-term arterial hypertension, often in patientspolycythemia or vasculitis. In 5% of cases (most often in patients over 65 years of age), neuropathy is associated with temporal arthritis.
Treatment of this type of vision loss requires urgent corticosteroid therapy to prevent loss of second eye vision. Diagnosis of temporal arteritis is simplified by the detection of painful induration, absence of temporal artery pulsation, and signs of polymyalgia rheumatica.
Rarely people lose their sight due to posterior ischemic optic neuropathy. It is usually caused by a combination of arterial hypotension and severe anemia, which may be the culprit for nerve infarction in the retrobulbar segment. Sometimes ischemic posterior neuropathy appears against the background of large blood loss during surgical interventions, trauma, and bleeding of the gastrointestinal tract. Transformations in the fundus are not found here.
In a hypertensive crisis, vision may suddenly drop due to ischemic swelling of the optic disc or spasm of the retinal arteries. Too rapid a decrease in blood pressure can lead to optic nerve infarction.
Loss of vision due to optic neuritis
Ocular neuritis is an inflammatory demyelinating disorder that often involves the retrobulbar segment of the nerve (retrobulbar neuritis), so initial fundus testing fails to detect pathology.
In many patients, in addition to acute loss of vision, there is pain in the eyeball, which increases with movement. More often loss of visionprogresses at a young age, may recur, and is often the first manifestation of multiple sclerosis. The treatment of vision loss of this form is performed by intravenous administration of impressive doses of "Methylprednisolone" (1 g per day for 3 days), which accelerates regeneration.
What happens with toxic neuropathy?
Toxic optic neuropathy can cause sudden loss of vision in both eyes. Toxic neuropathy can result from carbon monoxide, methyl alcohol, or antifreeze (ethylene glycol) poisoning.
A 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 optic discs (with brain tumors or benign intracranial hypertension). It is often preceded by brief episodes of blurred vision in both or one eye, which appear during the transformation of the body position and last a couple of seconds or minutes.
Therapy consists of the introduction of "Methylprednisolone" (250-500 mg intravenous drip) and an urgent consultation with a neurosurgeon and an ophthalmologist.
Occipital infarction
Suddenly appeared blindness in both eyes may be due to bilateral infarction of the occipital lobes(blindness cortical). It usually occurs as a result of prolonged arterial systemic hypotension or blockage of the basilar artery (usually as a result of an embolism). The source of embolism is usually atherosclerotic plaques located in the vertebral arteries.
Vertebrobasilar insufficiency with bilateral or unilateral paresis or paresthesia, dysarthria, ataxia, dizziness, hemianopsia, double vision usually occurs before vision loss.
Unlike bilateral blindness, which appears as a result of 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 is not blind, 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. An acute loss of vision may be psychogenic in nature and be one of the manifestations of hysteria. As a rule, such patients (more often young women) declare that everything around them is plunged into darkness (patients with cortical organic blindness often cannot describe their visual sensations).
The following hysterical symptoms are often found in the anamnesis:
- Mutism.
- Pseudoparesis.
- Hysterical fits.
- Throat lump.
- Hysterical gait disorders.
Against the background of acute loss of vision, pupillary reactions are usually standard, there are no stem symptoms. Unlikeof those around them, whose extreme anxiety and obligatory presence can serve as an additional diagnostic criterion, patients are often not alarmed, but rather calm, and sometimes even smile enigmatically (“beautiful indifference”).
Reasons for gradual loss of vision
If you feel a decrease in vision and constant fatigue of the eyeballs, this may be the result of incorrect reading, lighting or working at a computer. It is also possible that it is age related. But often the problems lie much deeper. Reasons for loss of vision (we do not take into account the computer, age and lighting here) are as follows:
- Fatigue is the most important cause of gradual vision loss. If a person does not eat properly, does not sleep enough, has regular stress, then the whole body suffers. Your eyes will give out your upset state in the first place. You yourself have probably noticed that the eyes after a stormy night are tired, painful and red. For many people, one hard working day is enough to come home with a tired, dull look.
- Another well-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 the result of a direct effect of harmful substances on the vessels of the eyes. The limited blood supply makes the eye vessels brittle and impairs vision.
- Also, vision may gradually deteriorate due to the presence of various infectious and venereal diseases.ailments in which the nerves are destroyed. Such damage affects the entire body, including the nerve endings that 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
Treatment of a disease of a secondary form caused by an ailment consists in the treatment of the underlying disease. In order to prevent the occurrence of various eye diseases and maintain vision, it is necessary to carry out prophylaxis in time. It is necessary to visit an ophthalmologist every year, who at the initial stages will reveal all conceivable pathologies.
You also need to follow simple rules - regularly rest your eyes, use good lighting, have the correct position when reading and writing, do exercises for the eyes.
You can also consider preparations that contain a complex of vitamins. These could be:
- "Retinol" (vitamin A). Affects the reproduction and growth of cells.
- "Tocopherol" (vitamin E). Prevents retinal detachment.
- Ascorbic acid (vitamin C). Responsible for tissue regeneration, collagen synthesis and blood clotting.
- "Thiamin" (vitamin B1). Contributes to standard intraocular pressure, and 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 blindness
What other causes of temporary vision loss are there? There is such a conceptas "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 stepped far forward, and now doctors can help patients with such a diagnosis 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 that tolerable for the optic nerve. Glaucoma develops for various reasons, but the development of this disease 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 should undergo a scheduled medical examination every year with an examination of the fundus and measurement of eye pressure (carried out by a local ophthalmologist in a polyclinic). Take care of your eyes and stay he althy!
