Definition
Diabetic retinopathy is a complication of the diabetes that results from the damage to the blood vessels of light-sensitive tissue at the back of the eye (retina). At first, diabetic retinopathy may not cause symptoms or only mild vision problems. However, diabetic retinopathy could cause blindness being one of the major causes in developed countries.
To protect your vision, it is necessary to take seriously the guidelines of care and prevention. Start a rigorous control of sugar level in the blood and the scheduling of semiannual eye exams, depending on the severity.
Symptoms
It’s possible to suffer diabetic retinopathy and not knowing about it. As a matter of fact, it is rare that the symptoms appear in the early stages of diabetic retinopathy.
As the disease progresses, symptoms of diabetic retinopathy appear and may include:
- Dark spots or floating filaments in your vision (floaters)
- Blurry vision
- Fluctuation of vision, during the course of the day.
- Dark areas or gaps in the visual field
- Poor night vision
- Deterioration of the color vision
- Total or partial loss of vision
Diabetic retinopathy usually affects both eyes, although it can vary in intensity.
When to visit a doctor
Careful management of your diabetes is the best way to prevent vision loss. If you have diabetes, consult your ophthalmologist for a dilated eye exam every year – although your vision does not seem to be affected – because it is important to detect diabetic retinopathy in the early stages. If you are pregnant, the retinal ophthalmologist may recommend additional exams during the pregnancy, because, sometimes, it can worsen diabetic retinopathy, although not as a rule.
Contact your doctor immediately if you experience sudden vision changes or if your vision turns blurred or cloudy or spots appear.
Causes
The excess sugar in the blood could damage the small blood vessels (capillaries) that nourish the retina. This can result in diabetic retinopathy and vision loss. The elevated sugar in the blood could also affect the eyes natural lens (crystalline) producing cataracts. With high levels of sugar for long periods of time, the crystalline may swell, causing blurred vision, too.
The Diabetic retinopathy is generally classified as early (non proliferative) or advanced (proliferative).
- Non Proliferative Diabetic Retinopathy. The Non proliferative diabetic retinopathy (NPDR) is the most common type of diabetic retinopathy. It can be classified as light, moderate or severe. When the NPDR is present, the walls of blood vessels in the retina are weakened. Small protuberances excel from the vessel walls, sometimes leaking fluid and blood in the retina. These protuberances are called micro aneurysms, which are the most common injuries of this disease. As the disease progresses, the smaller vessels can be closed and the small retinal veins may begin to be dilated and become irregular in its diameter (IRMAs). The retinal nerve fibers can also begin to swell by the accumulation of fluid and when it involves the central retina (macula) it is known as diabetic macular edema which is the leading cause of visual loss in diabetic patients.
- Proliferative Diabetic Retinopathy: The Proliferative Diabetic Retinopathy (PDR) is the most severe type of diabetic retinopathy. When the RDP is developing, abnormal blood vessels grow in the retina (neovascularization). These new blood vessels grow or get filtered toward the jelly-like substance that fills the center of the eye (vitreous humor). Eventually, scar tissue stimulated by the growth of these new blood vessels could cause the retina to detach from the back of the eye (tractional retinal detachment). If the abnormal blood vessels (neovascularization) interfere with the normal flow of fluid that regulates the pressure of the eye, it can accumulate in the eyeball, causing neovascular glaucoma that is very difficult to manage. This can irreversibly damage the optic nerve, which is responsible for carrying images from the eye to the brain.
Risk Factors
The diabetic retinopathy can affect anyone with diabetes. The risk is higher in the following conditions:
- Deficient control of the blood sugar level
- High blood pressure (arterial hypertension)
- Increased cholesterol level
- Pregnancy
- Smoker
- Overweight
- Sedentarism
The more time might have passed since the diagnosis of diabetes, the greater is the risk to develop diabetic retinopathy.
Complications
The diabetic retinopathy implies abnormal growth of blood vessels in the retina. The complications can lead to serious vision problems such as:
Vitreous Hemorrhage. New blood vessels can bleed into the vitreous (hemovitreous). If bleeding is mild, you could see only a few dark spots or floaters and in some cases it resolves itself spontaneously without the need of treatment. In more severe cases, the blood could fill the vitreous cavity and block your vision completely. The vitreous hemorrhage alone does not usually cause permanent vision loss. The blood often disappears within few weeks or months. Unless the retina may be damaged, the vision may return to its previous condition, otherwise it will have to be operated promptly.
Retinal detachment.
The abnormal blood vessels of diabetic retinopathy stimulate the growth of scar tissues (FVP - Fibro-Vascular Proliferation), which can cause retinal detachment. This can cause spot floaters in your vision, flashes of light or severe vision loss. It is important not to delay surgical treatment when this happens.
- Glaucoma. The new blood vessels can grow indiscriminately in the anterior part of the eye and interfere with its normal flow fluid, causing an exaggerated rise in eye pressure (glaucoma). This pressure could damage the nerve that carries images from the eye to the brain (optic nerve). nerve) in a permanent and irreversible manner.
- Blindness. Over time, diabetic retinopathy, glaucoma, or both of them can lead to total loss of vision, for this reason, the strict control of the disease is essential.
Diagnosis
The diabetic retinopathy is best diagnosed with an examination of the eye with dilated pupil. For this exam, the eye doctor will put drops in the eyes that will make your pupils dilate for several hours. This permits to obtain a better view of the structures within the eye and its anomalies. These drops may cause blurry vision, especially for near vision while the dilatation lasts, that could be from several hours to 48 hrs. It does not carry any ocular change.
During the examination, the ophthalmologist will look for:
- The presence or absence of a cataract
- Abnormal blood vessels
- Inflammation, bleeding or fatty deposits in the retina
- The growth of new blood vessels (neovascularization) and scar tissue
- Hemovitreous
- Retinal detachment
- Abnormalities in the optic nerve secondary to glaucoma
Besides, your oculist may be able to:
- Test your vision
- Measure eye pressure in order to detect glaucoma
The following additional studies may be requested by the physician to facilitate the diagnosis and follow-up to the respective treatment:
Fluorescein angiography (RFG)
As part of the eye exam, your doctor may request for a test called fluorescein angiography that consists on taking photographs of the retina. To perform the study, the pupils will be dilated and color images of the interior of your eyes will be taken. Then, a special dye (flourescein) will be injected in your arm vein. After that, more pictures will be taken to see how the dye circulates through the blood vessels inside your eyes. The retinal ophthalmologist can use the images to identify the blood vessels that are occluded, deformed or present fluid (contrast) loss and thus be able to make a proper diagnosis and define the best treatment.
Optical Coherence Tomography (OCT)
Your ophthalmologist may also request an Optical Coherence Tomography (OCT) as part of the eye exam. This imaging test provides cross-sectional images of the retina showing the thickness of this and all its layers, that will help to determine whether fluid has leaked in the retinal tissue and to quantify the damage. It is also a useful tool in monitoring the effectiveness of treatments in a noninvasive and quick way, without the need of placing an intravenous dye.
Treatment
Treatment for diabetic retinopathy is determined by the type of diabetic retinopathy, its severity, and how you responded to previous treatments.
• Early diabetic retinopathy
If you have non-proliferative diabetic retinopathy, it is possible that you may not need immediate treatment. However, the ophthalmologist will monitor closely your eyes to determine if you need treatment.
If it has not been possible to maintain a good control of your blood sugar level, you will need to consult with your diabetes specialist (endocrinologist) to determine further action to be taken for a better control of the disease. The good new is that when diabetic retinopathy is on mild or moderate stage, proper control of blood sugar can slow down the progression of diabetic retinopathy to advanced disease and dangerous stage.
If you have proliferative diabetic retinopathy, you will need immediate surgery. Sometimes surgery is also recommended for severe non proliferative diabetic retinopathy. Depending on the specific problems that affect the retina, the options could be:
• Focal treatment with laser.
This laser treatment, also known as photo coagulation, may stop or slow down the leak of blood and fluid from retinal blood vessels. It is done in the doctor’s office under local anesthesia (eye drops). During the procedure, abnormal blood vessels that present leakage are treated with laser burns. This focal treatment with laser is usually accomplished in a single session. Your vision will be blurry for about a day after the procedure. At times, you will notice small spots in your visual field that are related to treatment. These symptoms usually disappear within few weeks. If you had blurry vision secondary to macular inflammation (macular edema) before the surgery, you may not fully recover normal vision after the treatment.
• Complete Retinal Photocoagulation.
This laser treatment, also known as photocoagulation, can shrink the abnormal blood vessels and make them disappear, preventing leaks. It’s also performed in the doctor’s office under local anesthesia (eye drops). During the procedure, the areas of the retina away from the macula are treated with laser burns made ??in dispersed form. The burns make the abnormal vessels to shrink the size or heal. This treatment is usually performed in two or more sessions. Your vision will be blurry for about a day after the procedure. Some degree of loss of peripheral vision or night vision after surgery is possible.
• Vitrectomy. This procedure can be utilized to eliminate the blood inside the vítreous (hemovitreous) as well as scar tissue that is pulling the retina. This procedure is done in the operating room under local or general anesthesia. During the procedure, the doctor makes small incisions in the eye. The scar tissue and the blood inside the eye are removed with delicate instruments and replaced with a balanced saline solution (BSS),that helps to maintain the normal shape of the eye. Sometimes a bubble of gas should be placed in the cavity of the eye to help retinal reattachment in case of retinal detachment. If a bubble of gas is placed in the eye, patient must remain in a prone position until the gas bubble is reabsorbed, which could take several days. It will be pointed out to apply eye drops for a few days or weeks. The Vitrectomy could be followed or accompanied by laser treatment.
Surgery often slows down or stops the progression of diabetic retinopathy, but it’s not a cure. Because diabetes is a lifelong condition, the circumstantial damage to the retina and a future visual loss is a certain possibility. Even after treatment for diabetic retinopathy, you will need regular checkups with an ophthalmologist. If necessary, an additional treatment may be indicated.
At the present time new treatments for diabetic retinopathy are being implemented, including medications (antiVEGF and corticosteroids) that help to treat or to prevent the appearance of abnormal blood vessels formed in the retina .Some of these drugs are injected, in a painless way, directly into the eyes to get rid of abnormal blood vessels and the secondary retinal inflammation (macular edema).
Prevention
If you have diabetes, you can reduce the risk of diabetic retinopathy if you follow some advices:
• Commit yourself to manage your diabetes. Eat a healthy diet and make physical activity as part of your daily routine. Take the medications (oral diabetes medications or insulin) indicated by your diabetologist.
• Control your blood sugar. It is possible that you may need to check and record the blood sugar level several times a day – more frequent measurements may be necessary if you are ill or under high stress. Careful monitoring is the only way to ensure that your blood sugar level remains within an acceptable range. Ask your doctor to see how often you need to control sugar level.
Test of glycated hemoglobin.
The test of glycated hemoglobin or hemoglobin A1C reports the average level of blood sugar for the period of two to three months before the test, so, it’s a retrospective test of the illness. For most people, A1C should be less than 7. If you have been fulfilling your goals of maintaining low level of sugar in the blood, this test should be done twice a year. But, if your A1C is higher than expected, this test should be repeated more often. Remember, by maintaining your blood sugar as closely to normal as possible, the progression of diabetic retinopathy is slowed down and the need for treatment is reduced.
• Keep your blood pressure and cholesterol under control. The high blood pressure and the high cholesterol increase the risk of vision loss. The consumption of healthy foods, exercising regularly and losing weight is of great help. Sometimes additional medication is required in order to treat these diseases as well.
• If you smoke, ask your doctor to help you quit smoking. Smoking increases the risk of several grave complications of diabetes, including proliferative diabetic retinopathy. Talk to your doctor about how to go in order to quit smoking or to stop using other forms of tobacco.
• Pay attention to changes in vision. Annual eye check ups with dilatation are an important part of your diabetes follow up. Contact your ophthalmologist immediately if you experience sudden vision changes or blurred vision, or if you see spots.
Remember that diabetes does not necessarily lead to total loss of vision. Taking an active role in managing this situation can prevent serious complications or at least delay its appearance.
