Diabetic Macular Edema (DME)
Diabetic macular edema (DME) occurs when blood vessels in the retina of patients with diabetes begin to leak into the macula, the part of the eye responsible for detailed central vision. These leaks cause the macula to thicken and swell, progressively distorting acute vision. While the swelling may not lead to blindness, the effect can cause a severe loss in central vision.
DME is the major cause of vision loss in people with diabetic retinopathy. People with diabetes have a 10 percent risk of developing the condition during their lifetime. Alimera estimates that close to one million people in the United States alone currently have DME and approximately 300,000 new cases develop annually.
DME is classified into two types:
- Focal macular edema: caused by vascular abnormalities (primarily microaneurysms), which tend to leak fluid.
- Diffuse macular edema: caused by dilated capillaries in the retina.
The current standard of care for the treatment of DME is laser photocoagulation. Laser photocoagulation is a retinal procedure in which a laser is used to cauterize leaky blood vessels or to apply a pattern of burns to reduce edema. This procedure has undesirable side effects including partial loss of peripheral and night vision. As a result of these side effects and a desire for improved visual outcomes, retinal specialists have supplemented laser photocoagulation with non-FDA approved pharmacologic therapies for the treatment of DME, including injections of corticosteroids and anti-vascular endothelial growth factor (anti-VEGF) agents. Both of these therapies are limited by a need for multiple injections to maintain a therapeutic effect.