Diabetic retinopathy is the most common diabetic eye disease, it occurs when blood vessels in the retina change. Sometimes these vessels swell and leak fluid or even close off completely. In other cases, abnormal new blood vessels grow on the surface of the retina.
The retina is a thin layer of light-sensitive tissue that lines the back of the eye. Light rays are focused onto the retina, where they are transmitted to the brain and interpreted as images seen. The macula is a very small area at the center of the retina. It is the macula that is responsible for pinpoint vision, allowing you to use precise vision for everyday activities such as reading, sewing or recognizing a face. The surrounding part of the retina, called the peripheral retina, is responsible for peripheral vision (side vision).
Diabetic retinopathy usually affects both eyes. People who have diabetic retinopathy don’t often notice changes in their vision in the early stages of the disease. But as it progresses, diabetic retinopathy usually causes vision loss that in many cases cannot be reversed.
There are two types of diabetic retinopathy:
Non proliferative diabetic retinopathy (NPDR) is the earliest stage of diabetic retinopathy. With this condition, damaged blood vessels in the retina begin to leak extra fluid and small amounts of blood into the eye. Sometimes, deposits of cholesterol or other fats from the blood may leak into the retina. Many people with diabetes have mild NPDR, which usually does not affect their vision. However, if their vision is affected, it is the result of macular edema and macular ischemia.
Proliferative diabetic retinopathy (PDR) mainly occurs when many of the blood vessels in the retina close, preventing enough blood flow. In an attempt to supply blood to the area where the original vessels closed, the retina responds by growing new blood vessels. This is called neovascularization. However, these new blood vessels are abnormal and do not supply the retina with proper blood flow. The new vessels are also often accompanied by scar tissue that may cause the retina to wrinkle or detach.
PDR may cause more severe vision loss than NPDR because it can affect both central and peripheral vision.
When blood sugar levels are too high for extended periods of time, it can damage capillaries (tiny blood vessels) that supply blood to the retina. Over time, these blood vessels begin to leak fluids and fats, causing edema (swelling). Eventually, these vessels can close off, called ischemia. These problems are signs of (NPDR).
As diabetic eye problems are left untreated, (PDR) can develop. Blocked blood vessels from ischemia can lead to the growth of new abnormal blood vessels on the retina (called neovascularization) which can damage the retina by causing wrinkling or retinal detachment. Neovascularization can even lead to glaucoma, damage to the optic nerve that carries images from your eye to your brain.
You can have diabetic retinopathy and not be aware of it, since the early stages of diabetic retinopathy often don’t have symptoms, as the disease progresses, diabetic retinopathy symptoms may include:
The best treatment for diabetic retinopathy is to prevent it. Strict control of your blood sugar will significantly reduce the long-term risk of vision loss. Treatment usually won’t cure diabetic retinopathy nor does it usually restore normal vision, but it may slow the progression of vision loss. Without treatment, diabetic retinopathy progresses steadily from minimal to severe stages. There are however, treatments such as:
Treatments for Diabetic Retinopathy
The laser is a very bright, finely focused light. It passes through the clear cornea, lens and vitreous without affecting them in any way. Laser surgery shrinks abnormal new vessels and reduces macular swelling. Treatment is often recommended for people with macular edema, PDR and neovascular glaucoma.
Vitrectomy is a surgical procedure performed in a hospital or ambulatory surgery center operating room. It is often performed on an outpatient basis or with a short hospital stay. Either a local or general anesthetic may be used.
During vitrectomy surgery, an operating microscope and small surgical instruments are used to remove blood and scar tissue that accompany abnormal vessels in the eye. Removing the vitreous hemorrhage allows light rays to focus on the retina again.
In some cases, medication may be used to help treat diabetic retinopathy. Sometimes a steroid medication is used. In other cases, you may be given an anti-VEGF medication. This medication works by blocking a substance known as vascular endothelial growth factor, or VEGF. This substance contributes to abnormal blood vessel growth in the eye which can affect your vision. An anti-VEGF drug can help reduce the growth of these abnormal blood vessels.
SOURCE: What Is Diabetic Retinopathy? – Eye M.D.-approved information from EyeSmart. 2013. What Is Diabetic Retinopathy? – Eye M.D.-approved information from EyeSmart. [ONLINE] Available at: http://www.geteyesmart.org/eyesmart/diseases/diabetic-retinopathy.cfm. [Accessed 26 March 2013].