ABSTRACT
Background: Diabetic retinopathy (DR) is a leading cause of vision impairment, characterized by microvascular changes in the retina. The foveal avascular zone (FAZ) plays a critical role in maintaining central vision, and its enlargement is associated with disease severity in DR. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality that allows for detailed evaluation of retinal microvasculature, including the FAZ.
Aim: This study aimed to assess the size of the foveal avascular zone in patients with different stages of diabetic retinopathy using OCTA and to determine its correlation with disease progression.
Methods: A cross-sectional study was conducted on 30 patients diagnosed with various stages of diabetic retinopathy. OCTA was used to measure the FAZ area in both the superficial and deep capillary plexus. Patients were classified into non-proliferative DR (mild, moderate, and severe) and proliferative DR groups. Statistical analyses were performed to evaluate differences in FAZ size across the groups and to assess the correlation between FAZ enlargement and DR severity.
Results: FAZ size was found to be significantly larger in patients with advanced stages of diabetic retinopathy. The average FAZ area in the superficial plexus increased progressively from mild non-proliferative DR (0.26 ± 0.07 mm²) to proliferative DR (0.42 ± 0.11 mm²). Similarly, the deep capillary plexus showed a significant increase in FAZ size as DR severity advanced. A strong positive correlation (r = 0.81, p < 0.001) was observed between FAZ enlargement and DR progression.
Conclusion: OCTA provided valuable insights into the microvascular changes occurring in diabetic retinopathy. The enlargement of the foveal avascular zone was closely associated with disease severity, making it a potential biomarker for monitoring DR progression. Early detection of FAZ changes using OCTA could facilitate timely intervention and prevent further visual deterioration.
Keywords: Diabetic retinopathy, foveal avascular zone, optical coherence tomography angiography, retinal microvasculature, disease progression, OCTA