Diabetic macular edema (DME)
Diabetic macular edema (DME) is an accumulation of fluid in the macula which is the central portion of the retina that is responsible for central, high-resolution, color vision. DME can occur in individuals with either Type 1 or Type 2 diabetes, and it is a consequence of poorly controlled blood glucose that contributes to changes in the small vessels in the retina–a condition called diabetic retinopathy. Left untreated, diabetic retinopathy lead to blood or fluid accumulation on the retina, as well as causing swelling (edema) of the macula.
Diabetic eye disease is a leading cause of avoidable blindness worldwide, accounting for about 2.6% of all cases of global blindness. DME, which affects about 2 million Americans: about 10% of people with diabetes and about 70% of those with the most severe form of diabetic retinopathy, is known to contribute greatly to this vision loss.
Several known risk factors are known to contribute to the development of DME, including the length of time living with diabetes, unregulated blood glucose levels, poor diet, and history of cardiovascular disease.
Wet Age-Related Macular Degeneration (wet AMD)
Age-related macular degeneration (AMD) is an acquired degeneration of the macula. It is a highly prevalent clinical entity, affecting about 2 million Americans, with over 3 million cases expected by 2030 and over 5 million by 2050.
Between 10% and 15% of all AMD is the “wet” variety, which describes the growth of new, abnormal blood vessels under the retina and macula. The tenuous nature of this new vessel development makes them prone to leak or bleed, which leads to the characteristic loss of central vision in individuals affected by wet AMD. Significantly, wet AMD accounts for 90% of all vision loss caused by AMD.
Advanced age is the most prominent risk factor for AMD, and researchers have identified several genetic and epigenetic factors that interact to affect the disease process.
Macular Edema Following Retinal Vein Occlusion (RVO)
Retinal vein occlusion (RVO) occurs when the flow of blood from the retina is blocked. Based on the location of the blockage, RVO can be categorized into branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO), with BRVO occurring more commonly than CRVO.
Macular edema is the major complication causing the central vision loss in patients with BRVO or CRVO. Macular edema arises from breakdown of the blood retinal barrier at the capillary endothelium, resulting in the leakage of fluids into the retina, which causes blurring or loss of vision.
RVO is the second most common sight threatening retinal vascular disorder after diabetic retinopathy. Globally, an estimated 28.1 million adults are affected by RVO (4.7million by CRVO and 23.4 million by BRVO). Advanced age, hypertension, heart attack history, stroke history, higher level of total cholesterol and higher level of creatinine were risk factors for RVO.
