Diabetic Retinopathy
Scheie is a leader in research and treatment of diabetic retinopathy. The Retina Service offers the most advanced treatments, many of which have been developed or evaluated at Scheie.
What is Diabetic Retinopathy?
Over time, diabetes can damage small blood vessels throughout the body. This blood vessel damage can cause foot ulcers, nerve numbness and kidney failure. In the eye, it can cause retinal damage, known as diabetic retinal disease, or diabetic retinopathy.
Causes of Diabetic Retinopathy
People lose vision from diabetic retinopathy due to two major causes: swelling and bleeding. Swelling of the retina can occur when blood vessels leak fluid. When fluid leakage causes swelling in the central retina, or macula, vision becomes blurred. If diabetic retinopathy is severe, the retina becomes starved for oxygen. Blood vessels may then grow out of the retina or optic nerve into the vitreous jelly that fills the inside of the eye. These fragile vessels can cause bleeding into the eye and block light from reaching the retina. Without adequate light, vision is impaired. Bleeding can result in severe scarring, leading to retinal detachment.
Anyone with diabetes is at risk for diabetic retinopathy. The risk of developing diabetic retinopathy is related to the length of time one has diabetes and the severity of the disease. However, even people with newly diagnosed diabetes can have retinal disease that needs treatment. In addition, diabetic retinopathy can develop in people with excellent blood sugar control, even if the diabetes is mild and can be managed by proper diet. Women who have diabetes during pregnancy should be examined for diabetic retinopathy each trimester. Pregnancy sometimes can worsen diabetic eye disease.
Symptoms of Diabetic Retinopathy
Unfortunately, diabetic retinopathy typically has no symptoms in its earliest, treatable stages. By the time people notice a problem with their vision, retinal disease may be advanced and difficult to treat. This is why periodic screening examinations by your ophthalmologist are very important. Diabetic patients should have such examinations even if their vision is completely normal.
When macular swelling (edema) develops, central vision becomes blurred. Activities like reading and driving become difficult. Changing glasses will not improve the blurriness. When a hemorrhage (bleeding) occurs in the eye, spots or streaks of blood can be seen floating in your vision. If bleeding is more severe, or if it continues, a dense fog will blur vision. Occasionally, the blood will be so thick that a person will be able to see only light and dark. Often, blood will dissolve slowly over a period of weeks or months, and vision may improve. Sometimes, however, blood in the vitreous jelly will not clear without surgery.
Diagnosis of Diabetic Retinopathy
The only way to find out if you have diabetic retinopathy is to have a dilated examination of the retina. An examination to detect diabetic retinopathy will include drops to dilate the pupil. Your doctor can then look through the pupil with a bright light and a special magnifying lens to see the retina and any early signs of diabetic retinopathy. As people can develop diabetic retinopathy at any time, periodic eye examinations are important.
Treatment of Diabetic Retinopathy
Two forms of treatment have been proved to reduce vision loss from diabetic retinopathy: laser surgery and surgical removal of the vitreous jelly, known as Vitrectomy. If treated early enough in the course of the disease, a person has a greater than 90% chance of keeping some useful vision.
Laser surgery
Laser surgery is performed to treat macular swelling and to prevent bleeding from abnormal retinal blood vessels. This is an office procedure in which short bursts of light are used to treat the retina. Laser surgery can reduce vision loss from macular swelling (edema) by 50%. Laser surgery is much better at stabilizing vision rather than improving it. Therefore, laser treatment for edema is best done before a person notices blurred vision.
More extensive laser treatment can be used to prevent hemorrhaging from abnormal blood vessels that grow out of the retina or optic nerve. If bleeding is already present, laser surgery may not be possible because the vitreous fluid inside your eye is too murky to allow laser light to reach the retina. The doctor will sometimes wait for the hemorrhage to clear before doing this type of laser treatment. It is therefore better for a person not to wait until symptoms of a hemorrhage develop before laser treatment is done.
A laser beam is a light beam that can be placed with pinpoint accuracy. The laser makes a tiny spot (burn) to stop leakage from blood vessels or to make abnormal blood vessels shrivel up. Because the laser spots are so small, they are usually painless.
Laser surgery is performed in the doctor's office. Your pupils will be dilated with eye drops. Before the procedure, your ophthalmologist will numb the surface of the eye with drops. Sometimes, a medication is placed around the eye to prevent any discomfort. The eye doctor will hold a lens to your eye to keep you from blinking. The doctor will ask you to look in different directions with your other eye. During the procedure, you will see bright flashes of light and hear clicking sounds from the laser machine. The light flashes can be distracting, but not uncomfortable. When extensive laser treatment is done for bleeding, the flashes may eventually become a little uncomfortable.
Immediately after the laser, your vision will be blurred because of the bright lights and jelly used for the special laser treatment lens. Vision typically improves within several minutes and returns to its pre-treatment state within one to several hours, depending on the extent of treatment performed.
Laser surgery for macular swelling is usually done in one session. The treatment takes several weeks to work. Therefore, the doctor will need to see you again to check your progress. Laser surgery does not cure diabetic retinopathy. Therefore, more than one laser treatment may be needed.
Laser surgery for abnormal blood vessels with or without bleeding requires several hundred laser spots. This may take many treatment sessions done on different days. Some people will notice decreased side vision or decreased night vision after laser treatment to stop bleeding. This is a normal side effect and is usually mild. This treatment is necessary to prevent loss of center vision or of all vision.
The laser does not remove any blood that may be present. Therefore, floaters or spots in your vision will not necessarily go away after laser treatment. If there is no more bleeding, these hemorrhages may dissolve on their own. The laser treatment takes several weeks to work. Your doctor will see you to determine the need for any further treatment.
Vitrectomy
If there is blood in the eye that does not clear on its own, or if scar tissue causes a retinal detachment, you may need an operation called vitrectomy. In vitrectomy, the blood and scar tissue inside the eye are removed with miniaturized instruments. The vitreous fluid is replaced with a salt solution. Later, your eye fills itself with its normal, clear fluids.
Management and Prognosis of Diabetic Retinopathy
All people with diabetes should have an eye examination with pupil dilation at least once a year. You should not wait until symptoms such as blurred vision develop because permanent damage may be occurring. When retinopathy is serious, your doctor may need to perform eye examinations more frequently. Remember, laser surgery or vitrectomy cannot cure diabetic retinopathy. A person needs to be examined regularly to see if more treatment is needed.
Better control of blood sugar levels will help lessen diabetic eye disease. Good blood glucose control is especially helpful during early stages of diabetes. Keeping blood sugar levels close to normal reduces the need for treatment of diabetic retinopathy. Diabetics should contact their internists, family doctors or diabetes specialists about improving their blood sugar levels.
While good blood sugar control will reduce the chance of developing diabetic retinopathy, it will not prevent it completely. Slight elevations in blood sugar over a period of several years eventually will cause some damage to blood vessels in the retina. Therefore, all diabetics, regardless of how good their blood sugar control has been, need regular eye examinations for retinal disease.
It takes several years before good blood sugar control will have a beneficial effect on the retina. A person whose blood sugar has recently come under good control because of new medication will sometimes be found to have severe diabetic retinopathy. The retinopathy in this person has been developing for years before blood sugar came under good control.
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