The invention relates to a perimeter or a campimeter with a visible fixation point and a method used in them. The method comprises at least the following steps:producing a fixation point having a first visual appearance to be shown to a patient；producing a stimulus shown to the patient at a stimulus time-point at a pre-defined location；activating a response device by the patient upon noticing the stimulus at a response time-point；changing the fixation point to have a second visual appearance for a fixation point second visual appearance time interval near the stimulus time-point.
