Ophthalmology

Diabetic Retinopathy

Scheie's Retina Service offers the most advanced treatments for diabetic retinopathy, many of which have been developed or evaluated at Penn Medicine.

What is Diabetic Retinopathy?

Over time, diabetes can damage small blood vessels throughout the body. This 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

Anyone with diabetes is at risk for diabetic retinopathy, which causes vision loss due to two major issues: swelling and bleeding. Blood vessels in the eye sometimes leak fluid causing the retina to swell. This swelling causes blurred vision.

In severe cases the retina becomes starved for oxygen sparking the growth of blood vessels from the retina or optic nerve into the vitreous jelly that fills the inside of the eye. These fragile vessels can cause bleeding inside the eye and block light from reaching the retina. The result is impaired vision and possibly severe scarring, which can lead to retinal detachment.

Pregnancy can sometimes worsen diabetic eye disease, so women who have diabetes during pregnancy should be examined each trimester.

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Symptoms of Diabetic Retinopathy

Diabetic retinopathy has no symptoms in its earliest, most treatable stages. By the time it is discovered the disease may be advanced and difficult to treat. Diabetic patients should have regular examinations even if their vision is completely normal.

When macular swelling (edema) develops central vision becomes blurred which can affect activities like reading and driving.

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.

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Diagnosis of Diabetic Retinopathy

The only way to find out if you have diabetic retinopathy is to have an examination of the retina with 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.

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Treatment of Diabetic Retinopathy

Two forms of treatment have been used to reduce vision loss from diabetic retinopathy: laser surgery and surgical removal of the vitreous jelly, known as a Vitrectomy. If treated early enough in the course of the disease, a person has a greater than 90% chance of keeping some useful vision.

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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 for macular swelling is usually done in one session and can reduce vision loss 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. Lasers can be aimed with pinpoint precision. Because the laser spots are so small the procedure is usually painless.

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 does not cure diabetic retinopathy. Therefore, more than one laser treatment may be needed.

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.

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 and may take several weeks to work.

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.

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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 a vitrectomy. In a 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.

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Management and Prognosis of Diabetic Retinopathy

All people with diabetes regardless of how good their blood sugar control has been, need regular eye examinations for retinal disease. 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.

Better control of blood sugar levels will help reduce the chance of developing diabetic retinopathy, but it will not prevent it completely. Slight elevations in blood sugar over a period of several years will eventually cause some damage to blood vessels in the retina.

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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