DME is caused when fluid accumulates in the macula. It can develop without symptoms at any of the four stages of diabetic retinopathy (DR), though it typically occurs in the more advanced forms. It is found in almost 50% of people with proliferative retinopathy, the advanced stage of DR.
DME is a complex pathological process caused by multiple factors, including breakdown of the inner and outer blood-retinal barriers, oxidative stress, and elevated levels of vascular endothelial growth factor which have been demonstrated in both preclinical and clinical studies.
Current effective interventions for DME include treatment of systemic risk factors, such as elevated blood glucose, blood pressure and dyslipidemia. Ophthalmic treatments include laser photocoagulation, surgery and intraocular pharmacotherapy. New drugs, which are given by intraocular injection, have emerged in recent years to become first line treatment for DME that affects the central macula with loss of vision. Despite the use of molecular therapeutics targeting vascular endothelial growth factor (VEGF), the majority of patients do not recover good, functional vision, and show residual edema, necessitating repeated intravitreal injections. Early detection and treatment of DME can prevent vision loss that can be moderate to severe, and even permanent. Globally, 285 million people were estimated to be visually impaired in 2010, with 39 million completely blind. 21 million people were estimated in 2010 to live with DME worldwide.
Not only does vision loss drastically impede on the ability to live an independent high-quality life, its widespread prevalence also imposes a social and economic burden on individuals, communities and governments.