Currently, the domestic interests on the development of eyesight related measuring instruments are being increased. So we are developing such an electronic system of Refracto-keratometer, which contains a software and a hardware both. If this system could inform the examiner of the precise eyesight measuring result from the treatment of the image of optical system, then potentially the number of missed measuring results could be reduced. Our electronic system has been developed from the two areas divided into a software and a hardware. The software area was focused on the more exact eyesight measuring results, using morphological filtering methods and gray-leveled signal enhancing techniques. The hardware area is performing the same functions as the existing other systems. Besides, it provides the embedded software with free variables which could reduce the developing duration sharply as well as enlarge many kinds of application-extensions. Therefore, this electronic system has made effective eyesight measurement possible as the result of reducing the differences applied to sophisticated eyesight measurement.