Sugar diabetes – A complex disease that is not amenable to complete cure. However, modern medicine has ways to prevent severe retinal damage and maintain vision for long. Learn about them with Medaboutme !
Diabetes is very common. As of January 1, 2018, there were 4,264,445 patients with this disease in Russia. In recent years, there has been a rapid increase in the incidence of diabetes all over the world. At this rate, in 20 years, every tenth inhabitant of the Earth will have this diagnosis.
Damage to the retina is a typical complication of the disease. Ophthalmologists call this condition diabetic retinopathy. The probability of this event is the higher, the greater the experience of the disease. Thus, in type 1 diabetes after 20 years from the onset of the disease, this complication occurs in all patients, in type 2 diabetes – only in 2/3 of patients.
If untreated, diabetic retinopathy gradually progresses and leads to irreversible retinal damage. The result of the disease is blindness. This condition ranks fourth among the causes of visual disability.
Why does retina suffer?
The cause of diabetic retinopathy is damage to the small vessels of the retina – the capillaries. If sugar levels are elevated, excess glucose penetrates the endothelium. This is the innermost layer of the vessel, it is in contact with blood. Here glucose transformed into sorbitol. It is able to accumulate in the cell and significantly change the osmotic pressure. This leads to dysfunction of the endothelial cell and even its death.
Because of this, fibrin filaments are deposited on the inner surface of the vessel, and blood clots are easily formed that disturb blood circulation. The small retinal arteries are usually divided into two branches. When thrombosis of one of them in the “zone of responsibility” of the vessel there is a lack of oxygen – ischemia. This area is practically not supplied with blood.
Vessels accepting blood from the second branch, suffer from excessive pressure. Because of this, deformations of the vascular wall, microaneurysms , are easily formed , and capillary permeability increases. Local retinal edema occurs. The metabolism in this zone is also disturbed.
When these changes accumulate, the entire retina begins to suffer from a lack of oxygen. Its cells begin to secrete substances that promote the growth of new vessels. This is a vascular endothelial growth factor. The term VEGF ( Vascular Endothelial Growth Factor ). The amount of this substance in the cavity of the eye increases about 20 times.
Its enhanced production leads to the growth of new vessels. However, they are distinguished by a lack of muscle layer. A defective wall is easily damaged even with small fluctuations in blood pressure. This leads to retinal and vitreous hemorrhage. Such hemorrhage can significantly reduce vision. In addition, VEGF increases retinal vascular permeability. This aggravates the existing swelling.
In addition to vascular growth factor, other biologically active substances are also produced. They cause the growth of fibrous tissue. It takes away the remnants of vision and often leads to retinal detachment.
In the advanced stages of diabetic retinopathy, the newly formed vessels can not only occupy the entire area of the retina, but also grow into the angle of the anterior chamber of the eye. This is a small space at the junction of the iris and the cornea. It plays an important role in maintaining normal intraocular pressure.
With the proliferation of blood vessels there intraocular fluid outflow is hampered. This leads to a constant and significant increase in intraocular pressure. Such glaucoma is often accompanied by pain and leads to rapid loss of vision. This disease is difficult to treat.
Retinal Laser Coagulation
This method has been used to treat diabetic retinopathy for about 30 years. The energy of the laser beam is converted into heat and absorbed by the retina. Here occurs microburn , the result of which is inflammation. After his subsidence, scar tissue is formed. This is accompanied by the destruction of the retina and blood vessels in this area.
The amount of laser intervention depends on the area of damage to the retina. If she is involved entirely, use panretinal laser coagulation . If pathological changes are concentrated in one place, then the doctor performs focal laser photocoagulation .
Laser coagulates in the central part of the fundus are applied with great care. This zone is responsible for a clear vision of the contours of objects in daylight and the distinction of colors. Its damage threatens the violation of these important functions.
As a result of the procedure, part of the retina and blood vessels die. However, this has little effect on visual acuity. After all, the damaged area was responsible for peripheral and twilight vision. And the vascular growth factor is now produced much less. This significantly reduces the rate of progression of diabetic retinopathy. As a result, the sharpness of central vision remains high for a long time.
The effectiveness of coagulation confirmed by numerous studies. On a large number of patients it has been shown that after the intervention, good vision persists much longer than without it.
How is the procedure?
Laser coagulation begins with instillation of droplets to expand the pupil. Then local anesthesia is also carried out with the help of drops. However, some doctors prefer pain relief by injection into the space behind the eye.
Ophthalmic laser is always combined with a slit lamp. The patient is located behind the device. The doctor brings to the patient’s eye a special lens that allows you to see all the details of the fundus. He then applies the coagulum to the target area. If they are required a lot, the procedure is divided into 3-4 stages with an interval of 1-2 weeks.
In most patients, coagulation is accompanied by mild discomfort. After its implementation can also be discomfort. Perhaps a decrease in visual acuity by 1-2 lines. As a rule, these phenomena disappear after the inflammation in the eye subsides.
Drug treatment of diabetic retinopathy
The most commonly used anti-VEGF drugs. These are antibodies that bind only to the vascular growth factor, blocking its action. The result is the cessation of growth of newly formed vessels, the reverse development of existing neovascularization , a marked decrease in retinal edema. In this case, the patient feels the improvement of vision. According to one study, approximately 40% of patients reported an increase in visual acuity of several lines.
Only two drugs from this group are allowed for use in Russia. These are ranibizumab and aflibercept . Cost of these medication considerable, but in some clinics, this procedure can be obtained under the policy OMS. Bevacizumab was used for some time to be introduced into the eye cavity , however, many negative effects were noted. Now this tool is not recommended for use in ophthalmology, as indicated in the instructions for medication.
The drugs are injected into the cavity of the eye. This procedure is performed in the operating room under local anesthesia. Since the method is used relatively recently, there are no uniform recommendations on the number of injections and the timing of administration. Foreign ophthalmologists recommend doing at least 5 injections with an interval of 1-2 months.
The method has proven itself in diabetic edema of the macula. It is usually due to retinal ischemia and its widespread edema. At the same time, the neurons of the macular area squeeze and visual acuity decreases markedly.
The introduction of anti-VEGF drugs is also used in diabetic lesions of the entire retina. In this case, it is combined with coagulation . The combination of these methods is also effective in neovascular glaucoma.
If there are contraindications to the introduction of these drugs, or no result, corticosteroids may be prescribed. These drugs have a powerful anti-inflammatory effect, reduce macular edema. To get a lasting effect, a special preparation is injected into the cavity of the eye. The active substance is released from it within 3 months.
How to maintain vision in diabetes
Retinal damage is directly related to an increase in blood glucose levels. Therefore, to maintain the view it is very important to monitor this indicator. You can determine the level of sugar several times during the day.
But a more reliable indicator is the level of glycated hemoglobin. So he was called because of the strong connection with excess blood glucose. Therefore, its amount is directly proportional to the average blood sugar level. In patients with diabetes, this figure should not exceed 7%.
Otherwise, you should immediately contact the endocrinologist for treatment correction. In addition to glycated hemoglobin, the blood lipid spectrum and blood pressure should be regularly monitored.
Why do you need eye examinations
Regular examinations by an ophthalmologist are required. Unfortunately, this is not always the case. According to a survey conducted in one of the Russian regions, some diabetic patients with experience of up to 10 years have never been examined by an eye doctor. About half of the patients did not know that this should be done, the second half could not get advice because of the absence of a doctor in the community.
If initial changes in the retina are detected, all efforts should be made to stabilize the glucose level. When this goal is achieved, a reverse development of the pathological process in the eye is possible.
The main task of inspection is the timely detection of neovascularization . At this stage, the reverse development of the process is no longer possible even with the normalization of sugar levels. A timely treatment will permanently stop the progression of retinopathy and stabilize the vision.
Patients without signs of retinal damage should be examined by an ophthalmologist once a year, with initial changes once every six months. When neovascularization is detected, examinations should be performed at least 4 times a year. Such patients must be directed to laser coagulation of the retina and / or intraocular injection of drugs. Other methods of treatment of this pathology are not effective.