MACULAR MICROVASCULAR NETWORKS IN HEALTHY PEDIATRIC SUBJECTS ENRICO BORRELLI, MD,*†‡ MARCELA LONNGI, MD,†§ SIVA BALASUBRAMANIAN, MD, PHD,*† TUDOR C. TEPELUS, PHD,*† ELMIRA BAGHDASARYAN, MD,*† NICHOLAS A. IAFE, MD,†§ STACY L. PINELES, MD,†§ FEDERICO G. VELEZ, MD,†§¶ DAVID SARRAF, MD,†§** SRINIVAS R. SADDA, MD,*† IRENA TSUI, MD*†§** Purpose: To report optical coherence tomography angiography (OCTA) values in healthy pediatric eyes and to identify factors that may modify these values. Methods: In this prospective observational cross-sectional study, macular OCTA images were acquired from healthy pediatric patients. Main outcome measures were 1) foveal avascular zone (FAZ) area at the level of the superficial retinal capillary plexus (SCP); 2) SCP and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 3) SCP and DCP vessel density (based on a map with vessels of 1-pixel width); and 4) CC perfusion density. Multiple regression analysis was performed to assess the effect of age, sex, ethnicity, refraction, and foveal macular thickness (FMT) on OCTA parameters. Results: Seventy-seven eyes from 52 subjects (23 male and 29 female) were included in analysis. Mean age was 11.1 ± 3.3 years (range = 5.0–17.0 years). Twenty-nine (55.8%) subjects were white, 14 (27.0%) Hispanic, 8 (15.4%) Asian, and 1 (1.8%) African-American. Mean refraction was 20.1 ± 2.4 diopters (D) (range = 25.75 to +9.0 D). Mean FMT was 248.6 ± 18.6 mm. Larger FAZ area was significantly associated with older age (P = 0.014). Furthermore, larger FAZ area was associated with reduced FMT (P , 0.0001). Male sex was associated only with increased SCP perfusion density (P = 0.042). Increased CC perfusion density was associated with younger age (P = 0.022). Conclusion: We report data for pediatric OCTA parameters in healthy subjects. Several variables influence the density of macular microvascular networks, and these factors should be considered in the OCTA study of pediatric eye disorders. RETINA 0:1–9, 2018 T he macula is highly specialized neuronal tissue that includes the fovea which provides central visual acuity and contains the highest concentration of cones. In addition, the macula includes a high den- sity of rod and ganglion cells, making it one of the highest energy demanding tissues of the human body. The retina receives its oxygen and nutrient supply from both the retinal and choroidal vascular networks. 1,2 Fluorescein angiography (FA) and indocyanine green angiography (ICG) have traditionally been considered the gold standard for clinical assessment of the retinal and choroidal vasculature in vivo. These techniques play an important role in the evaluation and management of pediatric vascular disorders including Coats disease, 3 retinopathy of prematurity, 4,5 choroidal neovascularization, 6 and other ocular conditions. 7–9 Although dye adminis- tration is safe in pediatric patients, these techniques are considered invasive and require adequate patient cooperation with a needlestick. By contrast, optical coherence tomography angiography (OCTA) pro- vides noninvasive evaluation of the retinal and cho- roidal vascular circulations without the need for dye injection. 10 Furthermore, OCTA has the additional advantage of depth-resolution with better visualiza- tion of the deeper vascular layers such as the deep capillary plexus (DCP) and choriocapillaris (CC). Based on recent OCTA studies in adults, vessels located in the retinal nerve fiber and ganglion cell layers constitute the superficial retinal capillary plexus (SCP), whereas the intermediate capillary plexus (ICP) and the DCP are located at the inner and outer borders of the inner nuclear layer, respectively. These three capillary beds constitute the retinal capillary network, which is responsible for nourishing the inner and middle retina. 11,12 The retinal capillary network forms 1 Copyright ª by Ophthalmic Communications Society, Inc. Unauthorized reproduction of this article is prohibited.