OCT-Leakage Mapping: A New Automated Method of OCT Data Analysis to Identify and Locate Abnormal Fluid in Retinal Edema

Abstract

Purpose: To test OCT-Leakage, a new method of analyzing and mapping sites of lower optical reflectivity found on OCT, by examining eyes with various types of retinal edema to identify abnormal increases in retinal extracellular fluid. Design: Prospective analysis of a cohort of cases. Participants: Healthy eyes and eyes with retinal edema in the setting of different retinal diseases. Methods: Prospective OCT-Leakage analysis of 12 eyes with various types of retinal edema, such as diabetic macular edema, branch retinal vein occlusion, idiopathic perifoveal telangiectasia, and Irvine-Gass syndrome, representing intraretinal edema and eyes with idiopathic central serous chorioretinopathy and neovascular age-related macular degeneration representing subretinal fluid accumulation, in order to compare with OCT-Leakage analysis of a series of 41 eyes of 24 healthy controls. Raw scan data from the OCT images were exported and used to calculate lower than normal optical reflectivity maps (low optical reflectivity [LOR] ratios). Optical reflectivity LOR maps (OCT-Leakage maps) were collected for the full retina A-scan and layer by layer after segmentation. Low optical reflectivity ratios from patients with the different conditions of retinal edema and controls were compared. Fluorescein angiography (FA) and OCT angiography (OCTA) were performed in all eyes. Main Outcome Measures: Identification of areas of abnormal retinal fluid accumulation. Results: The OCT-Leakage maps based on sites of LOR (LOR ratios) delineated the location of intraretinal and subretinal fluid, always integrating the location of the sites on FA and the vascular abnormalities observed on OCTA. The areas of fluid outline in the OCT-Leakage maps were coincident and generally larger than those seen on FA. In all cases, the OCT-Leakage maps were able to identify the location of the fluid in the different segmented retinal layers. Conclusions: Mapping of lower reflectivity sites within the retina demonstrates the amount and location of retinal and subretinal fluid in different retinal diseases, showing potential to contribute to their management. Furthermore, the possibility of complementarity between OCT-Leakage and OCTA is highly promising.