Purpose To assess the ability of optical coherence tomography angiography (OCTA) to image the retinal middle capillary plexus (MCP), and to characterize the MCP as a unique vascular network separate from the superficial (SCP) and deep capillary plexus (DCP). Methods Healthy and diabetic eyes were imaged using the Avanti XR OCTA instrument (Optovue Inc, Fremont, California, USA). Using manual segmentation of the retinal layers, we generated en face angiograms to distinguish the three capillary plexuses (SCP, MCP, DCP). Results In healthy eyes, arterioles gave rise to distinct branches in the MCP, and venules gave rise to prominent vortex like branches in the DCP. The foveal avascular zone (FAZ) was most well-defined at the level of the MCP, and had a larger area in the DCP. In diabetic eyes, the three capillary plexuses showed varying degrees of non-perfusion, including variable shapes and extent of the FAZ, with loss of border integrity at the MCP. Microaneurysms appeared in all of the three capillary plexuses. Conclusions Using customized segmentation analysis in OCTA, we demonstrate that the MCP is qualitatively and functionally distinct from the SCP and DCP, which may help clarify the pathogenesis of different middle retinal ischemic entities and provide new insights into retinal ischemia in diabetic retinopathy.

Our findings support current theories that blood transfusions may have modulatory effects on the immune system of the recipients. Our specific study in spine patients may contribute to the expanding literature on allogeneic blood transfusions and the risk of nosocomial infections and encourage surgeons to favor a more restrictive policy with regard to transfusions.

IntroductionWound infections following spinal surgery place a high toll on both the patient and the healthcare system. Although several large series studies have examined the incidence and distribution of spinal wound infection, the applicability of these studies varies greatly since nearly every study is either retrospective and/or lacks standard inclusion criteria for defining surgical site infection. To address this void, we present results from prospectively gathered thoracolumbar spine surgery data for which the Centers for Disease Control (CDC) criteria were stringently applied to define a surgical site infection (SSI).

BACKGROUND AND OBJECTIVES: Construct a method for visualizing the middle capillary plexus (MCP) using Zeiss optical coherence tomography angiography (OCTA) and compare to established segmentation methods using the Optovue system. PATIENTS AND METHODS: Twenty eyes with diabetic retinopathy were imaged. Visualization of the MCP, image artifacts, preservation of pathological changes, foveal avascular zone (FAZ) area, and vessel length density (VLD) were compared between devices. RESULTS: The authors successfully segmented the superficial (SCP), MCP, and deep (DCP) capillary plexuses on both devices. More images artifacts were detected on Optovue. Microaneurysms and telangiectatic vessels were better visualized in the MCP on the Optovue. FAZ area showed a strong correlation between the two instruments (r2 = 0.666; P < .0001). The SCP had lower VLD compared to the MCP and DCP on both devices. CONCLUSION: The authors provide an objective and consistent method for manual segmentation using Zeiss OCTA to visualize the three retinal capillary plexuses.