A pump and probe fluorometer with a laser diode as single light source has been constructed for measurement of fast induction and relaxation of the fluorescence yield in intact cells, chromatophores and isolated reaction centers of photosynthetic bacteria. The time resolution of the fluorometer is limited by the repetition time of the probing flashes to 20 micros. The apparatus offers high sensitivity, excellent performance and can become a versatile device for a range of demanding applications. Some of them are demonstrated here including fast and easy investigation of the (1) organization and redox state of the photosynthetic apparatus of the intact cells of different bacterial strains and mutants and (2) electron transfer reactions on donor and acceptor sides of isolated reaction centers. The compact design of the mechanics, optics, electronics, and data processing makes the device easy to use as outdoor instrument or to integrate into larger measuring systems.

Our results reveal a significant interocular difference on PERG and PVEP recording, but this could not be ascribed to the anatomy of the retina and related visual pathways. If the difference between the eyes is not taken into account, misinterpretation may occur in a pathological process.

lower image resolution and it took longer to make fundus photographs with this smartphone set-up. Others show that smartphones can be used for more types of ophthalmologic imaging (Suto et al. 2014), though good image quality is still a prerequisite.The tested smartphone set-up, does not yet deliver fundus photographs of very high quality. However, point-ofcare diagnostics is becoming more important, and smartphone technology is developing rapidly. It is conceivable that smartphone technology combined with ophthalmic equipment can make clinically useful high quality smartphone images of the retina in the near future possible. Our results show that standard fundus photography currently remains first choice, to make retinal images of the highest quality.