Detection, localization, and characterization of vision-threatening features of microaneurysms using optical coherence tomography angiography in diabetic maculopathy

Abstract

Introduction Diabetic maculopathy is a leading retinal cause of blindness. This study was conducted using optical coherence tomography angiography and noninvasive imaging modalities. Microaneurysms were evaluated for location, flow, and adjacent retinal tissue changes to establish knowledge of possible vision-threatening features. Methodology: This is a hospital-based, cross-sectional observational study. Eighteen patients with diabetic maculopathy were included in the study. Fundus photo, red-free filter image, infrared images with shadowgrams, optical coherence tomography cross sections, and optical coherence tomography angiography were analyzed. Mean, standard deviation, odds ratio, and 95% confidence interval were used for statistical analysis, and p-value of <0.05 was considered statistically significant where applicable. Results A total of 64 microaneurysms were evaluated. Forty-six (71.8%) microaneurysms were identifiable in all imaging modalities. In total, 53 (82.8%) were high-flow microaneurysms and 11 (17.2%) were low-flow microaneurysms. Thirty-eight of the high-flow microaneurysms (71.6% of the high-flow microaneurysms) were found in the deep capillary plexus, while only 15 (28.4% of the high-flow microaneurysms) were found in the superficial capillary plexus. Twenty-seven (71%) of the high-flow microaneurysms in deep capillary plexus were present in the areas of retinal thickening (odds ratio: 4.5, 95% confidence interval: 1.26–16.0, p = 0.02). A total of 11 microaneurysms were classified as low-flow microaneurysms and identified using fundus photo, red-free filter image, infrared images with shadowgrams, and optical coherence tomography—cross sections. They had a tendency to be present in the areas of decreased capillary plexus density (odds ratio: 25.6, 95% confidence interval: 5.09–128.7, p = 0.001). Conclusion Noninvasive imaging modalities combined with optical coherence tomography angiography can provide valuable information regarding microaneurysms. Certain features such as location and flow may help in predicting impending macular edema or ischemia.