A retinal artery occlusion leads to mostly irreversible visual impairments due to the lack of oxygen supply to the affected part of the retina. If the central retinal artery is affected, the eye becomes blind in a short period of time because the optic nerve dies at the point where it exits the eye (blind spot) and the photoreceptors in the retina are extremely sensitive to a lack of oxygen.
What is a retinal artery occlusion?
A retinal artery occlusion is defined by a partial or total obstruction of the retinal central artery (Arteria centralis retinae) or one of its branches. A restriction or total blockage of the arterial blood supply in the retina directly affects the oxygen supply to the retina and its sensitive photoreceptors (cones and rods). For what does lsc stand for, please visit biotionary.com.
When a branch of the central artery is blocked, only a certain area of the retina is affected, resulting in a scotoma, a limited loss of visual field. If the central artery is affected, the eye becomes blind within minutes. Blindness becomes irreversible if oxygen can not be restored within 60 to 90 minutes.
The retinal artery occlusion can be caused by a disease of the retinal arteries themselves or by thrombi that have been washed in, which have formed, for example, in one of the two carotid arteries or in the heart.
Causes
Retinal artery occlusion can be caused by disease in the affected arteries themselves, or by blood clots that have spread from another region of the body and have broken away from where they originated. If the retinal arteries themselves are affected, it may be arteriosclerosis, in the course of which deposits form between the walls of the vessels.
Due to their space requirements, the deposits cause a narrowing (stenosis) of the artery, which can expand to a complete blockage. If arteriosclerotic diseases develop in one of the upstream arteries, such as the carotid artery, blood clots (thrombi) can form, which can break loose and accidentally lodge in the increasingly narrow branches of the arteries on their way to the target tissue.
Strictly speaking, an inundated thrombus is, by definition, an embolism. In some cases, retinal artery occlusion can also be caused by a rheumatic disease, temporal arteritis. It is an autoimmune disease, also known as Horton’s disease, in the course of which so-called epithelial giant cells form as a result of misdirected immune reactions in the inner vessel wall (intima) and can cause the artery to occlude due to spatial stress.
Symptoms, Ailments & Signs
Symptoms of a retinal artery occlusion are sudden and completely painless visual field loss or complete blindness. In some cases, the scotomas or total blindness resolve “on their own” within a few minutes.
This is amaurosis fugax (temporary blindness), which indicates a circulatory disorder in the brain or a stenosis of the carotid artery. Only in the case of disease of the arteries from Horton’s disease are scotomas and complete blindness also accompanied by severe headaches.
Diagnosis & course of disease
In the case of sudden and painless loss of vision or blindness, it is essential to act quickly because the sensitive photoreceptor cells in the retina are irreversibly damaged after just 60 to 90 minutes if there is a lack of oxygen. It is then no longer possible to restore vision. Any previous history can provide initial clues for a quick diagnosis.
The anamnesis is usually followed by the ocular fundus reflection, which usually reveals characteristic signs in the retina. Other important diagnostic methods are fluorescence angiography, in which the network of blood vessels and possible occlusions or stenoses are made clearly visible, and the measurement of intraocular pressure. With the exception of amaurosis fugax, retinal artery occlusion leads to irreversible blindness within 60 to 90 minutes if retinal oxygenation is not restored.
Complications
Retinal artery occlusion usually has a very poor prognosis. Blindness almost always occurs. This occurs very quickly, within 30 seconds of the event. However, if the treatment is immediate, there is a rare chance of still being able to see. However, if no treatment is given within an hour, the occlusion always leads to irreversible blindness.
The extent to which the retinal artery is affected is also decisive for the prognosis. If this affects only one branch of the artery, the prognosis is naturally more favorable. As part of the therapy, an attempt is made to dissolve the blood clot through fibrinolysis. However, even then it is only possible to save the affected eye in the rarest of cases. There is still a risk of reocclusion of the retinal artery if the underlying disease thought to trigger it persists.
This can eventually blind the second eye. In order to prevent this, the cause of the embolism must be thoroughly clarified and treated urgently. Patients with diabetes mellitus, high blood pressure, heart valve defects and arteriosclerosis are particularly at risk. A so-called giant cell arteritis also poses a great risk.
This is an inflammation of the vessels in the temporal arteries. A doctor should be consulted as a matter of urgency, especially if you experience a nagging headache that gets worse when you eat, as this can indicate a retinal artery occlusion or a stroke.
When should you go to the doctor?
In any case, this disease must be treated by a doctor. If left untreated, it can lead to complete blindness in the worst case. The earlier the disease is detected, the better the prognosis for the further course of the disease. In any case, the death of the optic nerve to the eye must be prevented. As a rule, the doctor should be consulted if the patient suffers from short-term loss of vision or vision.
The patient’s vision disappears for a short period of time. The entire sensitivity of the face can also be disturbed by the disease. Blood circulation disorders also indicate the disease. If these symptoms occur more frequently and do not go away on their own, a doctor must be consulted immediately. Severe headaches can also indicate the disease. The disease can usually be diagnosed by a general practitioner. In acute emergencies, the emergency doctor must be called immediately. This is the only way to prevent complete blindness.
Treatment & Therapy
Acute retinal artery occlusion initially requires immediate measures to restore the oxygen supply to the retina, if possible within an hour of the occurrence of the event. The ophthalmologist can try to massage the eye in a targeted manner in order to mechanically restore the patency of the artery. At the same time, drugs to lower the intraocular pressure are administered.
In some cases, an incision in the vitreous body (paracentesis) may be indicated and helpful. The incision makes it possible to “manually” control the outflow of fluid, thereby gradually and progressively reducing the drop in intraocular pressure. This softens the vitreous body. Ideally, the affected artery, which was previously slightly stretched and reduced in lumen, should be slightly dilated again.
In this way, the blood clot starts to move and, at best, dissolves again. If a thrombus has been identified as the cause of the arterial occlusion, a medicinal dissolution of the blood clot (lysis) can be attempted. If Horton’s disease is suspected, the only treatment option is treatment with high-dose cortisone.
Prevention
Direct preventive measures that could prevent retinal artery occlusion do not exist. However, there are different risk factors, the minimization of which indirectly also serves as an efficient preventive measure to avoid arterial occlusion in the retina. Risk factors include, for example, chronic high blood pressure (arterial hypertension), diabetes mellitus, and high alcohol consumption.
Heavy cigarette smoking and morbid obesity (obesity) can also be triggers. If several risk factors are present at the same time and cannot be reduced, the pros and cons of taking anticoagulants as a precaution should be discussed with an internist in order to fundamentally counteract the formation of thrombi.
Aftercare
Even during follow-up care, the consequences of a retinal artery occlusion (RAV) can only be diagnosed, but not completely cured. The severe visual loss associated with a central artery occlusion and the visual field limitations associated with a branch artery occlusion are generally permanent and cannot be cured. Follow-up care focuses on check-ups and psychological care for the patient.
Depending on the course and findings of the disease, ophthalmological check-ups should be carried out at least weekly in the case of a central artery occlusion and at least monthly (at the most three months) in the case of a branch artery occlusion. In addition, the ophthalmological aftercare can try to improve the retinal blood flow in the eye with medication or regular bulbus massages. In this way, further events can be counteracted if necessary.
It should be noted that all follow-up measures are recommendations of individuals or small groups based on retrospectively collected case numbers. Whether and to what extent the prescribed measures are effective has not been proven. The interdisciplinary cooperation with internal medicine, vascular surgery, neurology and interventional radiology is of central importance for the ophthalmological check-ups.
As a rule, retinal artery occlusion is a symptom or the result of a systemic cause (usually thrombosis). If the cause is not treated with medication, life expectancy can be shortened. Ongoing cardiovascular investigations therefore remain necessary even after the event. ECG checks, regular echocardiography and long-term blood pressure measurements are also useful. An annual Doppler echograph of the carotid arteries appears neurologically appropriate.
You can do that yourself
If symptoms suddenly appear in the eye that indicate a retinal artery occlusion, the emergency doctor must be called immediately. The patient must be kept still until the emergency services arrive. In the worst case, treatment that is delayed can lead to a stroke or even the loss of both eyes.
If available, an emergency drug such as cortisone must be administered in high doses. The prerequisite for this is that the causative circulatory disorder is already known. If there is no suspicion, the emergency doctor must be informed as precisely as possible about the symptoms and how they came about so that the necessary measures can be taken immediately.
Spontaneous improvement usually occurs only with incomplete closure. If not already done, possible triggers such as diabetes mellitus or arterial hypertension must be determined. These diseases must first be treated. If the course is severe, the patient suffers a stroke. Various self-help measures are useful in the event of a stroke. Which depends on the type and severity of the symptoms. The relatives should contact the responsible neurologist in this regard and develop a suitable treatment concept.
