Association of Body Mass Index, Blood Sugar and Glycated Hemoglobin Levels with Types of Macular Edema in Patients with Type-2 Diabetes Mellitus

Abstract

Diabetes mellitus (DM) is a metabolic disease defined by elevated blood glucose. DM is a global epidemic and the prevalence is anticipated to continue to increase. DM is can be further classified as type 1 (T1DM), which causes pancreatic beta cell failure due to which insufficient insulin is type 2 (T2DM) is characterized by insulin resistance [1]. Type II diabetes is most dominant form of diabetes contributing for almost 90% of total burden of diabetes [2]. Diabetic retinopathy is a cause of visual loss on a global scale. The pathology is closely associated with vascular, glial, and neuronal components of the diabetic retina. Treatments for the vision-threatening complications of diabetic macular edema and proliferative diabetic retinopathy have greatly improved. As per recent studies, diabetes markedly impacts the retinal neurovascular unit and its interdependent vascular, neuronal, glial, and immune cells [3]. Laboratory and clinical evidence show that, microvascular changes, inflammation and retinal neurodegeneration may contribute to diabetic retinal damage in the early stages of diabetic retinopathy [4]. Clinically, diabetic changes in the retina can be divided into two stages: non-proliferative diabetic retinopathy and proliferative diabetic retinopathy. Early stage of DR is represented by NPDR, wherein the pathology is increased vascular permeability and capillary occlusion. During this stage, the fundus findings include microaneurysms, hemorrhages and hard exudates while the patients may be asymptomatic4. Proliferative diabetic retinopathy is an advanced type of DR, the patients may experience severe vision impairment. This stage is characterized by neovascularization [4]. However, in addition to hyperglycemia, other factors like hypertension, dyslipidemia, and particularly the genetic load, have an immense influence on the severity and clinical course of diabetic retinopathy (DR) [5]. Using OCT, DME can be classified into four main types presented as the OCT Classification of Diabetic Macular Edema given by KolevaGeorgieva: [6]