Retinopathy, as it relates to the conditions covered in this article, refers to damage to the blood vessels of the retina. The retina, at the back of the eye, provides a window to the circulatory system. By examining it, a doctor can inspect a sample of the body's blood vessels and detect early signs of complications of diabetes or high blood pressure, as well as many other diseases (e.g., sickle cell disease, anemia, lupus). Retinopathy can also be seen in premature newborns.
Some of the kinds of damage that your doctor may see in your retina are hypertensive retinopathy, a complication of high blood pressure (hypertension), and diabetic retinopathy, a complication of long-term diabetes.
It's unusual for hypertension to impair vision, but hypertensive retinopathy can lead to blockage of retinal arteries or veins, which in turn may eventually result in the loss of vision. A combination of both hypertensive and diabetic retinopathy puts people at a higher risk of vision loss. Smoking and diabetes increase the risk of developing hypertensive retinopathy.
Diabetic retinopathy is a deterioration of the blood vessels in the retina that usually affects both eyes. It is the leading cause of blindness in North America. Almost all people with diabetes show signs of retinal damage after about 20 years of living with the condition.
Retinopathy is usually a sign of another medical condition. Although several medical conditions (e.g., sickle cell disease, lupus) can cause retinopathy, the most common causes are diabetes and hypertension (high blood pressure).
Diabetic retinopathy is a complication of diabetes. Diabetes causes high blood sugar levels, which can damage blood vessels. The damaged vessels in the retina can leak fluid, protein, and fats, forming deposits that can interfere with vision. The damaged blood vessels are not as effective at carrying oxygen to the retina, which can also cause damage.
In the advanced stage, called proliferative retinopathy, new blood vessels grow in the eye. However, they are weak and may burst, causing bleeding in the eye. The bleeding can cause scarring of the eye and damage vision.
Hypertensive retinopathy is a complication of high blood pressure that usually takes many years to develop. High blood pressure damages the blood vessel walls, causing them to thicken and narrow. This reduces the blood supply available to the retina, leading to retinal damage. Eventually, blood can leak into the retina, causing further damage.
Symptoms and Complications
Early in diabetic retinopathy, there may be no symptoms at all. As the disease progresses, symptoms include:
- blurred vision
- fluctuating vision
- seeing floating spots
- blind spots
- changes in color perception
- sudden loss of vision
- double vision
- eye pain in advanced cases
The earliest sign of diabetic retinopathy that your doctor may detect is the formation of microaneurysms. These are balloon-like outpouchings of small blood vessels in the retina that appear as tiny red dots at the back of the eye. They sometimes break, causing bleeding from the retina into the gel that fills the eye - the vitreous - as well as cloudy vision.
A more advanced form of diabetic retinopathy, called proliferative diabetic retinopathy, may lead to scars that decrease vision. In proliferative retinopathy, new blood vessels grow over the retina and into the vitreous.. These blood vessels may burst, causing bleeding and damage to the eye. The blood can be reabsorbed, but in some cases the retina can become detached causing total blindness.
As with diabetic retinopathy, there may be no symptoms early in hypertensive retinopathy. However, as the condition progresses, symptoms include:
- vision changes
- sudden loss of vision in one or both eyes
- double vision
Making the Diagnosis
Diabetic retinopathy is a long-term complication of diabetes. If someone has diabetes, it's extremely important that they have their eyes monitored and examined every 1 to 2 years, as recommended by an ophthalmologist (eye specialist).
Diabetic and hypertensive retinopathy are diagnosed in much the same way. An ophthalmologist will examine the retina with an ophthalmoscope, which shines bright light into the back of the eye and allows for a close look at the blood vessels of the retina. The ophthalmologist will look for signs of dilated blood vessels and microaneurysms (see the section "Symptoms and Complications"). They may also use fluorescein angiography, which involves injecting a dye into a vein of the arm and taking a series of retinal photos to detect signs of leaky blood vessels. This process can pinpoint areas that may be threatening to bleed.
In the case of hypertensive retinopathy, an ophthalmologist will look for tiny cholesterol-containing plaques in the retinal blood vessels as well as other blood vessel changes such as narrowing and thickening.
Treatment and Prevention
The key to treating retinopathy is managing the underlying causes of this condition.
Controlling blood sugar levels in diabetes is critical in delaying the onset of diabetic retinopathy. Proper management of diabetes involves taking the prescribed treatments, such as insulin or other diabetes medications, as well as following a healthy diet and exercise program.
Keeping blood pressure under control will help prevent hypertensive retinopathy. Reducing high blood pressure with appropriate medications will help prevent complications. Regular exercise, proper diet, and other lifestyle changes such as quitting smoking will go a long way toward reducing the risk of retinopathy.
The management of diabetic retinopathy includes laser treatment and medications injected into the eye (e.g., corticosteroids and vascular endothelial growth factor inhibitors). If a blood vessel has leaked into the vitreous and/or scarring has occurred, your doctor may advise you to have a vitrectomy. This procedure involves removing a part of the vitreous along with the scar tissue, if there is any, and may preserve vision or restore lost vision. If retinal detachment has occurred, surgery may be required to reattach the retina.
Treatment for hypertensive retinopathy includes medications to control blood pressure. Prevention is key for this condition.
If you have proliferative retinopathy, you should speak with your doctor before engaging in strenuous exercise.