Risk markers for progression of mild nonproliferative retinopathy to clinically significant macular edema in type 2 diabetic patients

Abstract

Abstract Purpose To determine risk markers for the development of clinically significant macular edema (CSME) needing photocoagulation treatment in type 2 diabetic patients with mild nonproliferative retinopathy (NPDR), during a 7‐year period. Methods Fifty‐one type 2 diabetic patients with mild NPDR, followed‐up for 2 years as controls of diabetic retinopathy clinical trials, were selected. Patients underwent ophthalmological examinations every 6 months, including stereoscopic color fundus photography, fluorescein angiography and vitreous fluorophotometry, and were metabolically controlled. These patients were thereafter followed‐up for the next 5 years by conventional general and ophthalmological care. Results At the end of the 7‐year follow‐up period, 8 patients developed CSME, needing photocoagulation treatment. These patients presented a higher microaneurysm (MA) formation rate at the first year of follow‐up (p<0.001), a higher blood‐retinal barrier (BRB) permeability value (p=0.042), an abnormal foveal avascular zone (FAZ) contour on fluorescein angiography (p=0.009) and a higher HbA1C level at baseline (p=0.001). Conclusion Microaneurysm formation rate higher or equal to 3 MA/year, BRB permeability values over or equal to 4.0 nm.s‐1, evidence of abnormalities in the FAZ, and hemoglobin A1C levels at baseline, are risk markers for progression of NPDR to CSME in patients with type 2 diabetes.