Abnormal blood vessel growth due to diabetes.
NVD – Neovascularization of the disc,
NVE – Neovascularization elsewhere.

What is it? Diabetes is a disease characterized by high sugar levels in the blood. This can lead to blood vessel damage throughout the body. When the blood vessels in the retina (the light-sensitive membrane lining the inside of the eye) are damaged, this is termed diabetic retinopathy.

How does diabetic retinopathy cause visual loss? The most common cause of decreased vision among diabetics is retinal swelling, also known as macular edema. Damaged vessels may become abnormally leaky allowing watery fluid to leak into the retina making it swollen. If this swelling affects the central retina (the macula), vision may become blurred. Visual loss may also occur secondary to the growth of abnormal blood vessels in the eye (neovascularization). Neovascularization may bleed filling the inside of the eye with blood (vitreous hemorrhage). Neovascularization may also contract, pulling the retina out of place (traction retinal detachment).

How is retinal swelling treated? If swelling affects or threatens the central vision, focal laser treatment is usually indicated. During focal laser treatment, very small spots of laser (< 1/5 mm) are used to seal leaky blood vessels in an attempt to reduce swelling. Laser treatment reduces the chance of future vision loss by 50%. Keeping blood pressure, sugar, and cholesterol under good control is also important for patients with retinal swelling.

While laser is usually successful, there are a small number of patients whose retinal swelling persists despite multiple laser treatments. For these patients, a recently developed procedure called intravitreal kenalog holds real promise. Kenalog (triamcinolone) is a long-acting steroid which can be injected inside the eye into the vitreous cavity. Steroids are known to reduce leakage from blood vessels prompting some doctors to try intravitreal kenalog as a treatment for retinal swelling which has failed to respond to laser. While this treatment remains investigational, it has shown excellent early results in research studies.

How is neovascularization treated? If vision is threatened by the growth of abnormal blood vessels, scatter laser treatment is often indicated. During scatter laser treatment, hundreds of small (1/2 mm) spots are applied to the peripheral retina. This treatment induces regression of the neovascularization in most eyes reducing the risk of bleeding or traction retinal detachment.

Does good sugar control reduce the chance of visual loss? Yes. The progression of retinal disease is reduced SEVEN-FOLD when sugar levels are tightly controlled.

How often should I have an eye exam? If you have diabetes, you should have a dilated eye exam at least once yearly, more frequently if you already have changes in the retina.

Do I need an exam even if my vision is normal? Yes! Many patients with retinal swelling or neovascularization see normally with absolutely no symptoms. These patients may be in urgent need of treatment to prevent visual loss from occurring. The only way this can be detected is with regular, dilated eye exams.

What is vitrectomy surgery? Vitrectomy surgery is an operation on the eye during which the vitreous gel inside the eye is removed and replaced with sterile saline solution. This operation is recommended for some patients with vitreous hemorrhage or traction retinal detachment to remove blood from inside the eye or flatten the retina.

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