What is Diabetic Retinopathy?
Diabetes is a very serious condition that can have an equally serious effect on the eyes. Anyone who has diabetes is at risk for developing diabetic retinopathy, a condition that can lead to partial or even complete vision loss. Diabetes can cause weakening in the body's blood vessels. The blood vessels in the retina are very susceptible to this weakening and can go through a series of changes . These changes may be leakage or closure from the tiny blood vessels (known as capillaries) or the growth of weak, new capillaries (neovascularization) that bleed very easily. Small bulges (known as microaneurysms) can develop in the walls of capillaries that leak fluid. The fluid causes the retina to swell (edema) as well as leave behind metabolic waste products known as exudates. If this swell develops near the center part of your vision (macula), the central vision may be reduced.
If the small retinal vessels close off (capillary closure or capillary dropout) the retina will become oxygen-starved (ischemic). When this happens, white patches of oxygen-starved retina (cotton wool spots) may remain.
This can lead to the growth of new blood vessels (neovascularization) which bleed and leak fluid easily. These vessels can form scar tissue, which the vitreous can pull. This can cause bleeding into the vitreous and/or detach the retina.
Types of Diabetic Retinopathy
Diabetic retinopathy has two main categories. Each of these categories has several sub-categories. These types are nonproliferative diabetic retinopathy (when blood vessels leak then close) and proliferative retinopathy (when blood vessels grow).
Non proliferative Diabetic Retinopathy
With a diagnosis of non proliferative diabetic retinopathy (also know as background retinopathy), your retina may have some capillary leakage and/or capillary closure. In the very early forms, leakage may be located in peripheral areas of your retina, away from your macula. You may have little if any visual symptoms. When leakage occurs in the macula, visual symptoms become more apparent. The swelling in the macula (edema), can be caused by a few leaking vessels or many scattered throughout the macula. This may cause slight to very severe blurring of vision. Finally, when the capillaries close the eye is at risk for new blood vessel growth.
Proliferative Diabetic Retinopathy
When the capillaries close, the retina becomes oxygen-starved. In response, the body grows new blood vessels in an attempt to nourish the retina. In the early forms, you may notice little change in your vision. These vessels are very fragile and if the vitreous pulls hard enough on them they can break, causing bleeding into the vitreous. This can cause the vision to be very blurry to completely obscured, depending on the severity. Scar tissue can also form around these vessels. If the vitreous pulls on this, it can cause a retinal detachment. This can cause severely reduced vision.
Diagnosis and Treatment for Diabetic Retinopathy
Patients coming for an exam are asked for a complete medical history. Knowing how long you’ve had diabetes, how you monitor and control it, as well as any specific visual problems you may be having help the doctor in the diagnosis. During your eye exam, your doctor will examine your retina through your dilated pupils for signs of diabetic retinopathy such as exudates or swelling from leaking blood vessels.
Patients with diabetic retinopathy may have 3D scans (OCT) done, to measure the changes in the retina from diabetes.
Patients with diabetic retinopathy may have retinal photographs taken. These photographs don’t serve any immediate diagnostic purpose. Rather, they are used during future eye exams. Your doctor can compare your retina to past visits to see if any changes have occurred in your condition. You may have them repeated from time to time.
If diagnosed with diabetic retinopahty, the doctor may recommend injections of medication called Avastin. After the eye is numbed with anesthesia, the medication is injeciton into the vitreous – or jelly-like substance in the back chamber of the eye. Avastin is administered by an injeciton into your eye as needed at regular intervals (about every four to six weeks); your ophthalmologist will tell you how often you will receive the injection, and for how long.
Sometimes these blood vessels can be treated with a laser. While the laser can’t restore vision that is already lost, it can help to prevent the abnormal blood vessels from spreading, which could make the vision worse.
Self-Help for Diabetic Retinopathy
Routine Eye Exams
If diagnosed with diabetes, you should have an eye exam done through dilated pupils at least once a year. If diagnosed with diabetic retinopathy, your ophthalmologist may want to see you several times a year to monitor your condition. Besides diabetic retinopathy, people with diabetes are more at risk for developing other eye conditions like cataracts and glaucoma.
Control Your Blood Sugar and Blood Pressure
While not fully understood, high blood glucose levels are likely to cause weakening of your blood vessels. It is important for you to control your blood glucose levels by testing your blood regularly, taking your medication if needed, and following your meal plan. Many diabetics also have high blood pressure. Keeping blood pressure under control may prevent retinopathy from become worse.
Blood sugar levels can be kept down by exercising regularly. Work with your primary care physician to determine what is the best form and amount of exercise you need.
From the American Academy of Ophthalmology