A system for computerised retinal haemorrhage analysis

BACKGROUND: Our aim was to develop an objective computerised system for measuring different types of retinal haemorrhages in differing digital images, for use as a research tool. Despite developing various fully automated systems of retinal haemorrhage measurement we ultimately found user interaction to be necessary to achieve satisfactory validity of segmentation, and developed an interactive system of haemorrhage assessment based on this. FINDINGS: The Haemorrhage Assessment System (HAS) presented here is an open access interactive program with graphical user interface allowing the ophthalmically trained user to easily delineate different haemorrhage types, optic disc and fovea. The system then automatically calculates a variety of measures, including mean haemorrhage area, total haemorrhage area, centre of mass, distance of centre of mass from disc and fovea, eccentricity and orientation. This paper presents evidence for the validity of HAS by comparison against established software and known results for geometric images. CONCLUSION: The system should be of use to experimenters studying the distribution and topography of vitreoretinal haemorrhages who require a means of accurately quantifying an ophthalmologist's gold standard assessment of a digital image.