Diabetic Retinopathy

Diabetes and Vision – Diabetic Retinopathy

Diabetes is a disease that concerns people of all ages. If you suffer from diabetes, your body does not use blood sugar properly. Diabetes can cause high levels of blood sugar, excessive thirst and urination. It can also cause vascular damage, on the veins and arteries that carry blood inside our body. One of its consequences is diabetic retinopathy, which means it can attack the retina (or, more simply, the fundus of the eye) in the form of damage to the vessels due to high blood sugar. There are no symptoms in the early stages, but, if it is not prevented, diagnosed and treated in time, the consequences for our eyesight might be very severe.

Since diabetes can affect our body in the above ways, it can also affect vision by causing cataract, glaucoma and – most importantly – damage in the vessels inside the eye.

What is diabetic retinopathy? What are its causes? Who should be concerned?

Diabetic retinopathy is a complication of diabetes caused by damage in the vessels of the eye. Retina is the neural layer in the posterior wall of our eye that receives light and helps send the images to the brain.
When these vessels in the retina are damaged, they can present fluid or blood leakage and develop fragile “brush-like” branches and scarring tissue. This might cause opacity or deformation of the images sent from the retina to the brain.
Diabetic retinopathy concerns every diabetic patient either insulin dependent (Type 1) and of young age or non-insulin-dependent (Type 2) and the disease has appeared later in life.

Diabetic retinopathy is a leading cause of primary blindness among adults in the entire western world and in Greece. It is believed that patients with untreated diabetes are under 25 times higher risk to go blind than the rest of the population.

The longer the time a patient suffers from diabetes, the bigger the risk to develop diabetic retinopathy.

Diabetes destroys the vessels in the retina and can cause leakage or abnormal hyperplasia.

About 80% of the patients that had diabetes for at least 15 years suffer today from some degree of vascular damage in the retina. Patients with Type 1 diabetes (young people's diabetes) are more likely to have diabetic retinopathy at a younger age. Even to them, however, this will usually happen after adolescence.

If you suffer from diabetes, it is important to know that today, with the new and improved diagnostic and treatment methods, only a small percentage of people who develop retinopathy face severe vision problems.

Clinical Image. Stages of diabetic retinopathy

1. Non-proliferative retinopathy.
In this stage, the fundus presents microaneurysms, hemorrhages, exudations and edema on the retina. When the leakage of the blood components towards tissues happens in the central point of the retina (the macula), then there is a macular edema. The above are a result of damage caused by diabetes to the small (capillary) vessels of the retina.

2. Proliferative retinopathy..
Due to poor blood circulation in the retina, zones of low oxygenation (ischemia) are created. The eye, by reacting to this condition, creates new pathological vessels, which are very sensitive and may bleed. The final stage of proliferative retinopathy includes hemorrhage in the vitreous, scarring, detachment, neovascular glaucoma and loss of vision.

What are the symptoms of diabetic retinopathy?

Diabetic retinopathy is a very insidious disease. Even if great changes are happening in the eye, the patient might present no symptoms and not realize the severity of his situation. Vision may not change until diabetic retinopathy has progressed to advanced stages.

Symptoms appear when there is an edema in the macula or hemorrhage in the vitreous or the retina, followed by loss of vision. When hemorrhage appears, your vision might become blurry, get filled with blurry spots or be gone completely. Diabetic patients often observe occasional haze, due to increases or decreases in blood sugar. Before using proper glasses to correct vision, we should first control our blood sugar. Finally, pregnancy and hypertension might worsen diabetic retinopathy.

What is the importance of an ophthalmology exam and how often must it be done?

The diabetic should undergo an ophthalmology exam regularly, even if there are no symptoms, in order to diagnose and treat retinopathy early. Remember that prevention is the best cure. In this particular case, regular visits to the ophthalmologist is what will probably save our vision.

 Fundoscopy (or ophthalmoscopy) through pupil dilation is the basic exam that each diabetic patient must undergo regularly. A visit to the ophthalmologist should occur every 6 months, if there are no other reasons for more regular examinations and if there is no damage to the fundus. If there is damage, then our visits should be 3-4 months apart. This way, the damage will be detected in time and indications for fluoroangiography will be found. This test, if necessary, is the next step, and an important weapon for a clearer diagnosis of diabetic retinopathy and of the state of the vessels. It is performed by injecting a dye (fluorescein) intravenously and photographing the fundus of the eye.

Optical coherence tomography (OCT) is the newest test to be used to diagnose diabetic maculopathy, which is the most important cause of decreased vision in diabetics. It is a form of tomography which uses infrared light to rapidly produce high definition tomographic images of the macula

Treatments for diabetic retinopathy 

The diabetic patient should know that the most important thing he needs to do for his condition is to keep his blood sugar under control. Blood sugar not under control causes a more rapid progress of diabetic retinopathy. He should also control his hypertension, his hyperlipidemia (cholesterol and triglycerides), if such exists, and limit smoking and alcohol. In any case, we should keep under consideration the following:
Your age
Your medical history
Your habits
The extent of the damage in the retina
In many cases, treatment is not necessary, but you will have to keep undergoing ophthalmology exams. In other cases, treatment is suggested, in order to stop any damage from diabetic retinopathy and, if possible, improve vision.

Intravitreal injection: With newer medicines, such as bevacizumab (Avastin), ranibizumab (Lucentis), to treat diabetic edema of the macula.

Laser surgery:This procedure often helps in treating diabetic retinopathy. A bright laser beam focuses on the damaged retina. Small doses of the laser beam can seal the leakage from the retinal vessels and decrease the macular edema. This is called photocoagulation.

For the abnormal neovascularization, the doses of the laser beam are diffused in the periphetal segments of the retina. The tiny scars from the laser decrease the abnormal vascularization and help bonds to develop between the retina and the posterior wall, functioning as a preventive measure against detachment.

During photocoagulation, the laser focuses on the retina to seal any leakage from the vessels and decrease abnormal neovascularization. If diabetic retinopathy is detected early, laser surgery can slow down loss of vision. Even in the most advanced stages of the disease, it decreases the chances of severe loss of vision.

Εάν η διαβητική αμφιβληστροειδοπάθεια ανιχνευθεί πρώιμα, η χειρουργική με laser μπορεί να επιβραδύνει την απώλεια της όρασης. Ακόμα και στα πιο προχωρημένα στάδια της νόσου, ελαττώνει τις πιθανότητες σοβαρής απώλειας της όρασης.

Cryotherapy: f the vitreous presents blood opacity, laser surgery cannot be used until the blood is stable or clear. In some cases of hemorrhage in the vitreous, cryotherapy or the “freezing” of the retina might help shrink the abnormal vessels.

Pars plana vitrectomy :In advanced cases of diabetic retinopathy, the ophthalmologist might recommend excision of the vitreous. This microsurgical procedure is only done in the operating room. Vitreous excision removes blurry vitreous and replaces it with a clear solution.

About 70% of the patients who underwent vitreous excision observe improvements after surgery. In some cases, the ophthalmologist can wait from a few months up to a year to see if this opacity might clear away on its own, before moving to vitreous excision.

Correction of the retina 

If scarring tissue detaches the retina from the posterior wall, the result might be severe loss of vision or even blindness, unless there occurs a procedure to restore the retina in its place.

What is your role in the treatment? 

The successful conclusion of diabetic retinopathy depends on the treatment which needs to be started immediately by your ophthalmologist. Your behavior and the attention you pay to your medication are very important. You should keep your levels of blood sugar low, avoid smoking and monitor your blood pressure. An important indication of successful treatment is to test for blood sugar and especially for glycated hemoglobin every three months. Physical exercise is usually not a problem to patients with diabetic retinopathy. It is often suggested to patients with active hyperplastic retinopathy to limit physical exercise.

Conclusion 

We need to realize the importance of prevention and early diagnosis. The diabetic patient should be examined often by his ophthalmologist, since that is the only way to predict changes in his eyes and treat the disease in a timely manner and in the best way for the situation.

News and Information 

Results from using Bevacizumab for diabetic retinopathy

Tags: