Diabetes affects 16 million Americans. In addition to causing numerous complications – from kidney failure to high blood pressure and cardiovascular disease – diabetes is one of the leading causes of blindness among working-age Americans. In fact, the National Eye Institute reports that diabetics are 25 times more likely to go blind than the general population, making diabetic retinopathy the leading cause of blindness in patients ages 20 to 74.
Forms of Diabetic Retinopathy
Diabetic retinopathy is an eye disease that affects the light-sensitive retinal tissue at the back of the eye. Diabetic retinopathy comes in two forms:
In this, the earlier and milder form of the disease, tiny blood vessels within the retina deteriorate. Some vessels may shrink, while others swell or form micro-aneurysms – weak spots where the blood vessel wall balloons out. The weakened blood vessels can leak fluid, causing the normally thin retina to swell. If the leaky vessels leave deposits that build up on the retina, it may cause blurry vision. Background retinopathy usually advances very slowly – and may not demonstrate symptoms for many years.
Twenty percent of diabetics with background retinopathy will develop this more severe progression of the disease. When this happens, new blood vessels actually grow on the retina or optic nerve. The weakened blood vessels can rupture and bleed into the clear center of the eye. The resulting blood can blur vision by blocking light from reaching the retina. The ruptured blood vessels create scar tissue that interferes with vision further. Long-term bleeding and scarring can cause the retina to pull away from the wall of the eye. If the retina detaches, the result is severe vision loss, which requires immediate surgery. The longer an individual has diabetes, and if it is poorly controlled, the higher the risk that it will progress to proliferative diabetic retinopathy and severe vision loss.
Anyone with diabetes is at risk – both people with Type I diabetes (juvenile onset) and those with Type II diabetes (adult onset). During pregnancy, diabetic retinopathy may also be a problem for women with diabetes. It is recommended that all pregnant women with diabetes have dilated eye examinations each trimester to check their vision.
The longer someone has diabetes, the more likely that he or she will get diabetic retinopathy. Nearly half of all people with diabetes will develop some degree of diabetic retinopathy during their lifetime. Because diabetes itself is often present for some time before it is first diagnosed, it is important that diabetic patients have a dilated eye exam when diabetes is first detected and at least once a year thereafter – even if no eye symptoms are apparent.
If you have diabetes, you are also at risk for other eye diseases. Studies show that you are twice as likely to get a cataract as a person who does not have the disease. Also, cataracts develop at an earlier age in people with diabetes. Cataracts are usually treated with surgery.
Glaucoma may also become a problem. A person with diabetes is nearly twice as likely to develop glaucoma as other adults. And, as with diabetic retinopathy, the longer you have had diabetes, the greater your risk of getting glaucoma. Glaucoma may be treated with medications, laser or other forms of surgery.
Background diabetic retinopathy may not exhibit any early warning signs. By the time the patient notices vision changes, the retinopathy is usually far advanced. That is why routine screening exams are recommended. As fluid leaks from the damaged retinal vessels, vision may become blurred. Glasses cannot restore this vision because the retina itself is damaged. Similarly, early proliferative retinopathy may not produce symptoms. However, bleeding can cause a sudden appearance of “floaters,” decreased acuity and, in some cases, an almost total loss of vision.
Macular edema also may develop. This blurs vision, making it difficult to read or drive. In some cases, vision will improve or worsen during the day.
As new blood vessels form at the back of the eye they, too, can bleed and blur vision. This can range from minor blood spots that appear as dark floaters to severe bleeding with significant loss of vision.
It may take a few days, months or even years to clear the blood from inside of your eye. In some cases, the blood will not clear.
In more advanced cases, the disease may progress a long time without symptoms. That is why regular eye examinations for people with diabetes are so important.
The best treatment for diabetic retinopathy is prevention – keeping your blood sugar under control. Even when retinopathy is diagnosed, early treatment can preserve your vision. Treatment depends upon multiple factors, including the type and degree of retinopathy, associated ocular factors such as cataract or vitreous hemorrhage, and the medical history of the patient.
Mild retinopathy may not require any specific eye treatment other than good control of your blood sugar. But if your vision is in jeopardy, more aggressive treatment may be suggested. It may begin with photographing your retinas to provide a baseline to determine if the disease is progressing. This also allows for the identification of leaky blood vessels, and provides a “road map” for possible surgical treatment. Treatment options include laser photocoagulation and vitrectomy surgery.
Laser surgery is done as an outpatient procedure and requires no surgical incision. A strong light beam is aimed onto the retina to treat the abnormal vessels. Laser surgery has been proven to reduce the risk of severe vision loss from proliferative diabetic retinopathy by more than 50 percent. If you have macular edema, laser surgery may also be used. In this case, the laser beam is used to seal the leaking blood vessels. But even laser treatment may not help advanced cases. In these situations, a procedure called vitrectomy may be recommended.
Vitrectomy may be required in advanced cases of proliferative retinopathy, especially when there is poor visibility within the eye due to blood and scar tissue. During this major eye surgery, the surgeon uses delicate instruments under the guidance of the operating microscope to remove the vitreous gel along with the scar tissue and blood.
However, surgery often cannot restore vision that has already been lost. That’s why finding diabetic retinopathy early is the best way to prevent vision loss. With timely treatment, the majority of those with advanced diabetic retinopathy can be saved from going blind.