A method for setting an evaluation parameter for a fluorescence microscope includes exciting dye particles in a sample to fluoresce and detecting fluorescent light from the particles. A graphical representation of a distribution of the fluorescent light is determined and a signal is generated for use in displaying the graphical representation on a display unit. Each subregion of the graphical representation is associated with a comparison value that is representative of a light quantity in the subregion. A predefined threshold is used as an evaluation parameter and compared to the comparison values. The subregions having a comparison value that is greater than the threshold value are marked on the display unit with predefined markings. The threshold value is changed and the comparison values are compared to the changed threshold value. The marked regions are defined as events and a complete image of the sample is obtained based on the events.