Area analysis of foveal avascular zone in diabetic retinopathy colour fundus images

Abstract

An enlargement of foveal avascular zone (FAZ) is usually found in eyes with diabetic retinopathy (DR). Currently, it is difficult to discern the FAZ area and to measure its enlargement in an objective manner using on colour fundus. A new automated approach for area analysis of FAZ using colour fundus images has been developed. Here, a binary map of retinal vasculature is computer generated from the colour fundus image and is then used to determine vessel ends and pathologies surrounding FAZ for area analysis. The performance of the developed method is compared to a manually-segmented FAZ from normal colour fundus image. The proposed method is found to achieve accuracies from 69.1% to 99.8% compared to accuracies of 16.6% to 98.9% for normal colour fundus images. The proposed method is more consistent with mean accuracy improvement of 16.1%. The standard deviation achieved by the proposed method is also smaller by a factor of 2.8. The developed algorithm is thus more reliable.