Optical coherence tomography‐based determination of ischaemia onset – the temporal dynamics of retinal thickness increase in acute central retinal artery occlusion

Abstract

Acute central retinal artery occlusion (CRAO) induces ischaemic retinal oedema. The purpose of this study was to define sensitivity and specificity of optical coherence tomography (OCT) based retinal thickness analysis in determining ischaemia onset in CRAO. The relative retinal thickness increase (RRTI) in comparison with the fellow eye was analysed retrospectively in OCT scans of 66 patients diagnosed with CRAO between January 2010 and December 2019 within 48hr of ischaemia onset. The natural course of RRTI and the sensitivity and specificity of OCT-based determination of ischaemia onset in identifying CRAO within 4.5hr using the RRTI were evaluated. Relative retinal thickness increase (RRTI) in acute CRAO follows a hyperbolic curve with a steep incline within the early phase after which it reaches a plateau. Optical coherence tomography (OCT)-based retinal thickness analysis in CRAO allows to differentiate patients with ischaemia onset within the past 4.5hr or thereafter with a sensitivity of 100% and a specificity of 94.3%. Relative retinal thickness increase (RRTI) allows to identify CRAO patients that are eligible for a potentially beneficial reperfusion therapy within a therapeutic window of 4.5hr with a high accuracy. Especially in patients with unknown ischaemia onset, this diagnostic tool could be of major importance in the future clinical management.