August is eye health awareness month, and a common condition that affects the eye, especially in India, which bears a staggeringly high burden of diabetes, is diabetic retinopathy. Here is all you need to know about it.
What is diabetic retinopathy?
Diabetic retinopathy is an eye disease caused by diabetes. It is the leading cause of vision loss and preventable blindness in working-age adults (20 – 65 years), worldwide. When a person has high blood sugar, this can damage the blood vessels in the retina, which is the layer inside the eye that detects light and is critical for vision. The risk increases with uncontrolled diabetes and in people who have had diabetes for a long time. Anyone with any type of diabetes — type 1, type 2 or gestational diabetes — can develop diabetic retinopathy. It usually affects both eyes.
How does the damage occur?
The retina is nourished by a series of tiny blood vessels. Over the course of years, high sugar levels damage these blood vessels. The damage causes the blood vessels to swell up and leak. It can also cause the vessels to close, stopping blood from passing through. In advanced stages, abnormal new blood vessels can grow on the retina.
Diabetic retinopathy is progressive. There are two stages:
Non-proliferative diabetic retinopathy: This is the early stage, and many people with diabetes have it. At this stage. At this stage, the blood vessels weaken and swell, sometimes leaking blood and fluid into the retina. If there is a build-up of fluid, or edema, this can cause swelling in the central portion of the retina or macula. This macular edema is a common cause of vision loss. The body may also try to contain the damage, causing the blood vessels to close off. This is known as macular ischemia — as blood cannot reach the macula.
Proliferative diabetic retinopathy: This a more advanced stage of the condition. At this stage, since some blood vessels have been closed off, new blood vessels form, to try and supply undernourished parts of the retina — neovascularization. However, these may be fragile and bleed into the vitreous, the clear, gel-like matter between the lens and the retina. Over time, these new blood vessels can also form scar tissue, which can cause the retina to detach from the eye. This stage of the condition is very serious.
Signs and symptoms
In the early stages of diabetic retinopathy, some people may have no symptoms at all — it’s only when the damage is severe that it starts to affect vision.
Once the condition progresses, symptoms may include: floaters, blurred vision, colours appearing faded, dark/empty areas in the field of vision and loss of vision.
Risk factors apart from having diabetes for a long time and poorly-controlled blood glucose levels, include hypertension, high cholesterol levels, and smoking among others. Heart disease, coronary artery disease and chronic kidney disease are other risk factors.
Diagnosis and treatment
An eye examination is needed to diagnose diabetic retinopathy. This would involve the use of drops to dilate the pupil. Other tests may include optical coherence tomography (OCT) for cross-sectional images of the retina and fluorescein angiography, which involves the use of an injected dye, to look for leaking, blocked and abnormal blood vessels.
Treatment for diabetic retinopathy depends on how severe the condition is. Good blood sugar control is key to slowing and delaying symptoms. This includes taking prescribed medication, following a diet, and maintaining an optimal weight. This apart, managing blood pressure is also important.
For the advanced stage of the condition, medication may be required. These include injections to bring down the macula swelling or may include corticosteroids.
Other treatment options include laser surgery, where laser is used to shrink or seal abnormal and leaking blood vessels. More than one session may be needed. Another option is a surgery called vitrectomy. This involves removing blood from vitreous haemorrhages or treating certain types of retinal damage.
Early diagnosis and treatment should be the goal, as certain types of damage to the eye caused by diabetic retinopathy cannot be fully reversed. Controlling blood sugar and blood pressure levels, keeping track of any changes in vision and regularly consulting an eyecare provider are steps that can go a long way.
