Treatment of Diabetic Retinopathy and Macular Edema
How is a macular edema treated?
Macular edema is treated with laser treatment, injection of medications into the eye, or both. Focal laser treatment involves the application of small laser burns to distinct areas of leaky blood vessels within the macula, whereas grid laser treatment applies laser burns over a larger area of the macula and is used to treat more widespread fluid edema. These laser burns slow the leakage of fluid and reduce the amount of fluid in the retina. This treatment is usually completed in one session, but additional treatments may be needed. Laser therapy of macular edema may or may not improve vision, but has been proven to decrease the chances of further vision loss over time by 50% based on the landmark Early Treatment of Diabetic Retinopathy Study. Medications injected into the eye for macular edema include steroids and so-called VEGF inhibitors (for example, Lucentis™ and Avastin™). These treatments have been shown to decrease retinal swelling and improve vision in patients with diabetic macular edema. Steroids and anti-VEGF drugs are increasingly being used in tandem with laser treatment.
A patient may need focal laser surgery more than once to control the leaking fluid. If you have macular edema in both eyes and require laser surgery, generally only one eye will be treated at a time, usually several weeks apart.
Focal laser treatment stabilizes vision. In fact, focal laser treatment reduces the risk of vision loss by 50%. In a small number of cases, if vision is lost, it can be improved. Contact your eye care professional if you have vision loss.
What are the side effects of treatments for macular edema?
Both focal and grid laser treatment may result in new, small blind spots in a person's vision. Steroid injections may result in elevated internal eye pressure and glaucoma that requires treatment. The newer anti-VEGF medications appear to have a good safety profile overall (similar drugs used intravenously to treat colon cancer have shown a small but definite increased risk for blood clots), but often require multiple injections over time.
Photos Courtesy of the National Eye Institute
How is diabetic retinopathy treated?
No treatment is needed during the first three stages of diabetic retinopathy unless a patient has macular edema (although research suggests that laser treatment may be effective for severe nonproliferative retinopathy in some patients with type 2 diabetes). To prevent progression of diabetic retinopathy, people with diabetes should control their levels of blood sugar, blood pressure, and blood cholesterol.
The gold-standard for treatment of proliferative retinopathy is laser therapy. The doctor applies 1000 to 2500 laser burns throughout the peripheral retina (areas outside of the macula). This procedure is referred to as panretinal photocoagulation (PRP) or scatter laser treatment, and helps to shrink abnormal blood vessels that bleed into the eye and cause retinal detachment. Because a higher number of laser burns is necessary, two or more sessions usually are required to complete treatment. PRP has been proven to reduce the chances of severe vision loss from proliferative retinopathy by up to 75%. Importantly, PRP works better before the fragile, new blood vessels have started to bleed. That is why it is important to have regular, comprehensive dilated eye exams. If bleeding or fibrous scar tissue growth are severe, patients may need a surgical procedure called a vitrectomy. During a vitrectomy, the vitreous gelatin filling the inside of the eye and blood contained therein are removed, thereby improving vision and reducing the risk of any or further retinal detachment. More recently, anti-VEGF drugs are starting to be used in addition to PRP for the treatment of proliferative retinopathy.
Scatter laser treatment works better before the fragile, new blood vessels have started to bleed. That is why it is important to have regular, comprehensive dilated eye exams. Even if bleeding has started, scatter laser treatment may still be possible, depending on the amount of bleeding.
If the bleeding is severe, you may need a surgical procedure called a vitrectomy. During a vitrectomy, blood is removed from the center of your eye.
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