Optical Coherence Tomography Angiography in Early Detection of Microvascular Changes in Type I Diabetic Children: A Systematic Review and Meta-Analysis

Abstract Background: Diabetic retinopathy (DR) is one of the leading causes of blindness worldwide, especially in the pediatric population. Accurate investigative tools are essential for the early diagnosis and monitoring of the disease. Aim of Study: To conduct a systematic review and a meta-analysis to detect the early retinal microvascular changes in diabetic eyes with no clinical signs of diabetic retinopathy (DR) on routine fundus examination using optical coherence tomography angiography (OCTA) in pediatrics. Patients and Methods: From a total of 217 screened citations, seven studies met our inclusion criteria with a total of 708 cases and 1228 eyes. The main outcomes were foveal avascular zone (FAZ) area and perimeter, Acircularity index, non-flow area (mm2), SCP and Foveal density (%) along with superficial (SCP) and deep capillary plexus (DCP). Data Extraction: If the studies did not fulfill the inclusion criteria, they were excluded. Study quality assessment included whether ethical approval was gained, eligibility criteria spec-ified, appropriate controls, and adequate information and defined assessment measures. Results: Our results suggested several potential biomarkers that could detect early DR in diabetic patients particularly in FAZ perimeter (MD =0.10, 95%CI=[0.03, 0.17], I2=31%, p-value=0.23) and Foveal density (%) (MD=–1.48, 95%CI= [–2.27, –0.70], I2=15%, value=0.28). Additionally, we pooled data regarding vessels densities and found that a trend towered a lower SCP vessel densities in the whole retina and Parafoveal area (MD=–0.96, 95%CI=[–1.38, –0.55], I2=32%, value =0.23 and MD=–0.87, 95%CI=[–1.20, –0.53], I2=0%, value =0.82, respectively) and lower DCP vessel densities in Parafoveal area (MD=–1.02, 95%CI=[–1.35, –0.70], I2=8%, value=0.35). Conclusion: OCTA enables quantitative evaluation of the microvasculature of diabetic eyes. It has demonstrated the ability to detect early changes in FAZ perimeter and SCP and DCP in the eyes without clinical evidence of DR. It has also been shown to detect progressive changes in the FAZ diameter, and vascular perfusion density, with worsening severity of disease. Additional studies with larger sample size are needed to validate our findings.