The relevant parameter is the optical resolution or the resolving power of the EasyScan. This means what are the smallest objects that can be detected? That is for the EasyScan 15┬Ám and is determined by the optical system of the device but also the eye it self. What does this value mean? This means when can for example still image the smallest blood vessels near the macula, see picture below. This is critical to be able to detect the subtlest changes easily.