Intravitreal inserts of steroids to treat diabetic macular edema

Diabetic retinopathy is the leading cause of blindness in developed countries. Diabetic macular edema (DME) is the most frequent cause of vision loss in patients with type 2 diabetes. Steroids may reduce the concentration of inflammatory cytokines and growth factors, and have effect on increased vascular permeability. Topical steroids does not reach intraocular therapeutic concentrations and periocular injection requires frequent injections at the risk of complications. Systemic administration of steroids may be useful, but high doses are required and are associated with severe systemic side effects. Intravitreal injection of steroids provides a powerful therapeutic effect, but it is associated with frequent secondary cataracts and increased IOP. The need for repeated injections may increase the risks associated with the injection procedure. Preliminary studies have proved the possibility of implanting sustained release inserts in the vitreous body, allowing for therapeutic levels of steroids in the vitreous cavity and retina for more than six months. The advantages of these systems are to keep a stable and sustained concentration of the drug with higher therapeutic efficacy thus reducing the number of injections. However, the complications associated with the use of steroids such as cataracts and high IOP are very common.