Retina

What is Diabetic Retinopathy?

Diabetic retinopathy, the most common diabetic eye disease, is caused by changes in the blood vessels of the retina. There are two types of diabetic retinopathy: background or nonproliferative diabetic retinopathy (NPDR); and proliferative diabetic retinopathy (PDR).

A Normal Retina

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A Retina Showing Signs of Diabetic Disease

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Proliferative Diabetic Retinopathy (PDR)

Proliferative diabetic retinopathy (PDR) occurs when abnormal blood vessels begin to grow on the surface of the retina or optic nerve. This is called neovascularization. PDR mainly occurs when many of the blood vessels in the retina close, preventing enough blood flow. The retina responds by growing new blood vessels in an attempt to supply the area where the original vessels closed. However, the new blood vessels are abnormal and do not supply the retina with normal 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.

PDR causes vision loss in the following ways:

How Diabetic Retinopathy Is Treated

The best treatment is to prevent the development of retinopathy. Strict control of your blood sugar will significantly reduce the long-term risk of vision loss. Treatment will not usually cure diabetic retinopathy or restore normal visual acuity, but it may slow the progression of visual loss. Without treatment, diabetic retinopathy progresses steadily from minimal to severe stages.

Laser Surgery

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, proliferative diabetic retinopathy (PDR), and neovascular glaucoma.

Laser surgery is usually performed in an office setting. For comfort during the procedure, an anesthetic eye drop is often all that is necessary, although an anesthetic injection is sometimes given next to the eye. The patient sits on an instrument called a slit-lamp microscope. A contact lens is temporarily placed on the eye in order to focus the laser light on the retina with pinpoint accuracy.

For macular edema, the laser is applied near the macula in order to reduce fluid leakage. The main goal of treatment is to prevent further loss of vision by reducing the swelling of the macula. It is uncommon for people who have blurred vision from macular edema to recover normal vision, although some will experience partial improvement.

A few people may see laser spots near the center of their vision following treatment. They usually fade with time, but may not disappear completely.

In PDR, the laser is applied to all parts of the retina except the macula (called PRP, or panretinal photocoagulation). This treatment causes abnormal new vessels to shrink and often prevents them from growing in the future. It also decreases the chance that vitreous bleeding or retinal distortion will occur. Panretinal laser has proven to be very effective in preventing severe vision loss from vitreous hemorrhage and traction retinal detachment.

Side effects of panretinal laser surgery may include:

Temporary blurred vision for days to a few weeks;
Occasional mild loss of central vision;
Mild to moderate loss of peripheral vision;
Decreased night vision.

Multiple laser treatments over time may be necessary. Laser surgery does not cure diabetic retinopathy and does not always prevent further loss of vision. In spite of laser surgery, some people with PDR develop macular distortion or bleeding into the vitreous, causing blurred vision. Vitreous hemorrhage may recur and blood may accumulate faster than the eye can reabsorb it.

The Center for Eyecare Retina Services

Diabetes is a disease which can be controlled but not cured. Early diagnosis of diabetic retinal diseases, close follow-up care, and lifetime monitoring are key to maintaining good vision. Dr. Raymond M. Girgis is trained to treat diabetic retinal diseases. With his background in Internal Medicine, Dr. Girgis is uniquely qualified in the evaluation and treatment of this disease. In many cases, the treatment can be successfully achieved with retinal laser procedures. In more advanced cases, surgical operations must be performed.