The invention relates to a device and a method for examining the retinal vascular endothelial function of the vessels of the retina at the fundus (F) of a patient's eye. Using a fundus camera, the vessels of the retina are stimulated with flicker light during a stimulation phase and sequences of images of areas of the fundus (F) are recorded, from which vascular parameters are derived which describe the retinal vascular endothelial function of the vessels. By imaging a macula aperture (MB), which covers the macula, onto the fundus (F), the fundus (F) can be illuminated with a higher light intensity, which improves the stimulation effect and the image quality and/or reduces the strain on the patient.