Features of the development of moderate diabetic macular edema in patients with type 2 diabetes in the short-term follow-up
Authors: Suk S.A. 
Published: January 2025

Background. Diabetic macular edema (DME) is one of the main complications of diabetic retinopathy, which occurs in almost 12 % of patients and causes more than 10,000 new cases of blindness per year. About 5 % of patients with type 2 diabetes already have DME at the time of diagnosis. Thanks to the ra­pid development of research methods such as optical coherence tomography (OCT) and OCT-angiography, the possibilities of measuring retinal layer thickness, visualizing retinal and choroidal vessels have significantly expanded. The purpose of the study is to investigate the features of moderate diabetic macular edema (DME 2) in patients with type 2 diabetes. Materials and methods. Six hundred and eighty patients (1296 eyes) of the Ukrainian popu­lation with nonproliferative diabetic retinopathy and type 2 diabetes were under observation. In them, the nature and frequency of DME development were studied. Two hundred and three patients (360 eyes) with DME refused treatment, and eyes with DME 2 were selected from this group, and these patients were the target of our study. All of them were examined for uncorrected visual acuity, best corrected visual acuity, OCT and OCT-angiography indicators at presentation and after 3 months. Results. Moderate diabetic macular edema was detected in 56 eyes (15.56 %). Uncorrected visual acuity in these patients averaged 0.310 ± 0.004. Best corrected visual acuity was 0.4 ± 0.0 on average. According to OCT data, the average area thickness in quadrant 6 × 6 was 321.80 ± 1.40 μm, the minimum thickness of the retina in the fovea was 213.41 ± 2.30 μm, the average thickness of the retina in the central sector of the macula — 245.57 ± 2.50 μm, the average retinal volume in quadrant 6 × 6 — 9.23 ± 0.03 mm³, nerve fiber layer (NFL) + ganglion cell layer (GCL) + inner plexiform layer (IPL) average — 127.73 ± 0.10 μm, NFL + GCL + IPL min — 117.8 ± 0.1 μm, average thickness of GCL — 91.54 ± 0.20 μm, of NFL — 38.84 ± 0.10 μm. During OCT angiography, the surface area of the superficial foveal avascular zone (FAZ) was on average 0.51 ± 0.01 mm², the surface area of the deep FAZ was 0.59 ± 0.01 mm². The average density of the superficial capillary plexus was 47.75 ± 0.40 %. The average density of the deep capillary plexus was 48.52 ± 0.30 %. After 3 months, according to OCT, area thickness was 321.45 ± 1.34 μm, min in fovea — 213.41 ± 2.32 μm, central sector — 246.0 ± 2.4 μm, volume — 9.23 ± 0.03 mm³, NFL + GCL + IPL average — 127.52 ± 0.10 μm, NFL + GCL + IPL min — 117.59 ± 0.20 μm, GCL — 91.21 ± 0.20 μm, NFL — 38.84 ± 0.10 μm. According to OCT-angiography, superficial FAZ averaged 0.53 ± 0.01 mm², deep FAZ — 0.61 ± 0.01 mm². The ave­rage density of the superficial capillary plexus was 47.7 ± 0.4 %. The average density of the deep capillary plexus was 48.46 ± 0.40 %. Conclusions. The average frequency of DME 2 in patients with type 2 diabetes was 15.56 %. Uncorrected visual acuity appeared to have a statistically significant dependence on the area thickness (p < 0.01), min in fovea (p < 0.01), central sector (p < 0.01), NFL + GCL + IPL average (p < 0.01), NFL + GCL + IPL min (p < 0.01), GCL (p < 0.01), NFL (p < 0.05) according to OCT data, as well as on the average area of foveal avascular zone in the superficial and deep capillary plexus (p < 0.05), the density of the superficial and deep capillary plexus (p < 0.01) according to OCT angiography.