Abstract
Purpose: :
To determine risk markers for development of clinically significant macular edema (CSME) needing photocoagulation treatment in type 2 diabetic patients with mild nonproliferative retinopathy, during a 7-year period.
Methods: :
Patients selected for this observational retrospective cohort study, patients with type 2 diabetes and mild nonproliferative retinopathy, were followed-up for 2 years as controls of diabetic retinopathy clinical trials and underwent ophthalmological examinations every 6 months, including stereoscopic color fundus photography, fluorescein angiography, vitreous fluorometry, and were metabolically controlled by a diabetologist. All 51 patients’ eyes were followed-up for the next 5 years by conventional general and ophthalmological care. Photocoagulation for CSME was given according to well defined guidelines. Treatment was given based on findings from color fundus photography and fluorescein angiography. At the 7th year of follow up a review of the medical history was performed.
Results: :
At the end of the 7-year period of follow-up, 8 of the 51 patients had developed CSME (main outcome of this study). These 8 patients presented a higher HbA1C level at baseline (p=0.001), a higher microaneurysm formation rate at the first year of follow-up (p<0.001), a higher blood-retinal barrier (BRB) permeability value (p=0.042) and an abnormal foveal avascular zone (FAZ) contour on fluorescein angiography (p=0.009).
Conclusions: :
Hemoglobin A1C values at baseline, microaneurysm formation rate higher or equal to 3/year, BRB permeability values over or equal to 4.0 nm.sec-1 and evidence of abnormalities in the FAZ are risk markers for progression of nonproliferative retinopathy to clinical significant macular edema in patients with diabetes type 2.
Keywords: edema • diabetic retinopathy • retina