The invention relates to an assembly for generating a variable illumination for diagnosis and therapy, in particular of the human eye. The illumination and irradiation unit consists of an illumination source that emits light, elements for generating special illumination patterns and/or profiles, in addition to elements for coupling the light from the light source into the parallel beam path of the viewing system of the ophthalmologic device. The inventive solution generates different marks, patterns and profiles and can also be used both for diagnosis and therapy in ophthalmology. The illumination unit is therefore suitable for different ophthalmologic devices. It can also be configured as a modular unit for retroactive assembly in the parallel beam path of an ophthalmologic device. To achieve this, a beam divider that is already present in the respective ophthalmologic device is used. The illumination and irradiation unit can also be used as an independent unit or as an auxiliary unit for various ophthalmologic devices, such as slit lamps, fundus cameras, laser scanners, ophthalmoscopes and operating microscope systems.