**4. Treatment of DME**

## **4.1 Systemic control**

The control of all systemic risk factors is vital in the treatment of DME. Optimizing control of diabetes, hypertension, and serum lipids should be emphasized. Optimization of care involves visits to the internist. The intervention aims to reduce glycated hemoglobin, elevated blood pressure, and elevated serum lipids to produce measurable effects in macular thickness in as little as six weeks [114].

The Diabetes Control and Complications Trial (DCCT) reported that tight blood glucose control in patients with type 1 diabetes reduced the cumulative incidence of macular edema at 9-year follow-up by 29% and reduced the application of focal laser treatment for DME by half [115, 116].

The United Kingdom Prospective Diabetes Study (UKPDS), a randomized clinical trial of patients with type 2 diabetes, reported that tighter blood glucose control reduced the requirement for laser treatment at ten years by 29%, compared with looser control; 78% of the laser treatments were for DME [50]. This study also demonstrated that a mean systolic blood pressure reduction of 10 mm Hg and a diastolic blood pressure reduction of 5 mm Hg over a median follow-up of 8.4 years led to a 35% reduction in retinal laser treatments 78% were for DME [51].

The Action to Control Cardiovascular Risk in Diabetes (ACCORD) eye study compared the progression of DR in a Simvastatin plus placebo group, Simvastatin plus fenofibrate group. The rate of progression of DR was lower in the fenofibrate group than in the placebo group [117].

High plasma cholesterol may be associated with more severe hard exudates at the macula [118, 119]. It has been reported that oral Atorvastatin reduced lipid migration to the subfoveal region and decreased the severity of hard exudates in type 2 DM patients with dyslipidemia who had CSME [120]. Nephropathy and anemia can contribute significantly to the risk of DR and DME. Weight loss and cessation of smoking are also crucial in preventing DR and DME.
