Non-invasive biomarkers for close activity monitoring in birdshot chorioretinitis: Optical coherence tomography angiography and beyond.

PURPOSE: The purpose of the study was to identify non-invasive imaging biomarkers potentially useful for close activity monitoring in birdshot chorioretinitis (BSCR). METHODS: Cross-sectional study of BSCR eyes included as per Levinson's and/or SUN criteria. Eyes were blindly classified into active or inactive groups per clinical inflammatory parameters, ultra-widefield (UWF) pseudocolour images, UWF fluorescein angiography (FA) and macular optical coherence tomography (OCT) cube. Qualitative and quantitative OCT and OCT-angiography (OCT-A) parameters at the fundus, superonasal and inferonasal fields were compared between active and inactive eyes. RESULTS: Thirty consecutive BSCR patients (60 eyes) were analysed. 28 eyes (46.66%) were from women and the overall mean age was 59.7 ± 12.3 years. Active eyes showed an abnormal retinal thickening at inferonasal field (nasal retinal thickness) and a higher averaged thickened retinal index (ATRI) (72.36 active vs. 20.12 inactive, p < 0.0001). A significant moderate correlation was observed between ATRI and FA scores (r = 0.259, p = 0.022). Macular vascular loops were more frequent in the superficial vascular plexus of OCT-A in the active eyes (p = 0.028). The vascular perfusion index tended to be higher in all subfields of active eyes but did not reach statistical significance. CONCLUSION: Multimodal imaging could be key to discerning activity in BSCR eyes. Higher ATRI and the presence of vascular loops in the superficial plexus are potential non-invasive activity biomarkers for the close monitoring of BSCR.

Evaluation of microvascular changes in the perifoveal vascular network using optical coherence tomography angiography (OCTA) in type I diabetes mellitus: a large scale prospective trial.

BACKGROUND: Diabetic retinopathy (DR) is the leading cause of blindness in type 1 Diabetes Mellitus (DM) patients, as a consequence of impaired blood flow in the retina. Optical coherence tomography angiography (OCTA) is a newly developed, non-invasive, retinal imaging technique that permits adequate delineation of the perifoveal vascular network. It allows the detection of paramacular areas of capillary non perfusion and/or enlargement of the foveal avascular zone (FAZ), representing an excellent tool for assessment of DR. The relationship of these microvascular changes with systemic factors such as metabolic control or duration of the disease still needs to be elucidated. METHODS: Prospective, consecutive, large-scale OCTA study. A complete ocular examination including a comprehensive series of OCTA images of different scan sizes captured with 2 OCT devices (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA, USA, and Triton Deep Range Imaging OCT, Topcon Corp, Topcon, Japan) will be obtained as part of the yearly routine follow up visits in type 1 DM patients seen in the Diabetes Unit of the Endocrinology department which give written informed consent to participate in the project. The aim of this study is to investigate the relationship between OCTA-derived parameters and systemic factors, as metabolic control (Hb1Ac, lipid profile, cholesterol, etc), and other relevant clinical factors as demographics or duration of the disease. DISCUSSION: This study is directed to investigate the relationship between the status of the perifoveal vascular network and systemic markers of the disease, and in particular to study whether these changes reflect those occurring elsewhere in the body affected by diabetic microvascular disease, as the kidneys or the brain. If these relationships were demonstrated, early detection of these microvascular changes by OCTA could lead to modifications in the pharmacological management of type 1 diabetic patients, as a way to reduce the risk of future complications in both the eye and other organs. TRIAL REGISTRATION: ClinicalTrials.gov, trial number NCT03422965.