“…Virtual colored overlay that can be used on PC was first introduced in the world as Virtual Reading Ruler [ 7] and it was first developed in 2008 in Korea too [8]. Recently, a kind of virtual colored overlays in mobile device has been developed; however, it can't be applied to all contents of its environment [9,10]. Therefore, it is an urgent requirement to develop assistive devices that improve accessibility to electronic documents for those with visual stress.…”