OCT angiography - new views of the retina

Abstract

Introduction: Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging technique that generates volumetric angiography images in a matter of seconds. Thanks to a special processing OCTA can produce images of capillary-level blood flow in the retina and choroid in a few seconds. The project seeks a correlation between Flow Density and Structural and Functional Chang­es in patients with normal tension, hypertensive glaucoma and suspected glaucoma. Materials and Methods: The technology allows the deeper structures to be visualized and even low microvascular flow to be detected with high sensitivity. OCTA is a fast, non-invasive, 3-D alternative to fluorescein angiography. The main aim of the method is to detect inside layers and intravascular flow. This method has a rapid scanning and real time eye tracking system. OCTA can be used for a lot of ophthalmologic diseases such diabetic retinopathy, arterial and venous occlusions, glaucoma. In the project 50 patients were examined (91 eyes) grouped as glaucoma, normal tension, and suspected. Using the OCT, Angio OCT methods and experimental software the flow density of the papilla and peripapillary area were calculated. Results: OCTA is a technology which extracts the signal changes derived from vascular flow using multiple OCT B scans acquired at the same position. It demonstrates high sensitivity for the detec­tion of low blood flow in microvasculature. The tracking system detects eye movements and blinks in­stantaneously and modifies the scan position to ensure complete scanning of all areas. The project es­tablished a strong correlation between peripapillary vascular density and the conducted research, one between vascular density and structural and functional changes in the optic nerve. Conclusion: Standard OCT structural imaging reveals micron-scale morphological changes in the retina while OCTA detects functional impairment in retinal and choroidal vasculature at the capil­lary level. The OCTA gives a chance to discover what lies beneath the surface.