[The eye of the inner clock - pupil research in a new light]. / Das Auge der Inneren Uhr - Pupillenforschung in neuem Licht.

BACKGROUND: Pupillary research has received a new impetus since the discovery of the melanopsin containing ganglion cell subpopulation ipRGC (intrinsically photosensitive retinal ganglion cells). These specific ganglion cells have a maximum spectral sensitivity at 480 nm and affect predominantly the day-night cycle (inner clock) and the pupil reaction. They control above all the adjustment of the pupil width during continuous lighting, as well as during particularly bright and above all short wavelength light. Our results from blind patients with retinitis pigmentosa also showed clear pupil light reactions when examined with standard pupillographic equipment (CIP, AMTech, Dossenheim) with a yellow stimulus. These results are difficult to explain with the previous hypotheses. Up till now, there have been only few investigations in groups of patients with ophthalmological diseases. These studies indicate that with modified pupillographic stimuli, a clear distinction between lesions of the outer and inner retina is possible. METHODS: It is of interest for future applied pupillary research to ascertain how the pupillary light reaction alters with the wavelength, duration and intensity of the light stimulus. For such studies it is necessary not only to use well-defined spectral stimuli but also to develop special recording techniques and methods of analysis. CONCLUSIONS: It is to be expected that the results of such research will have consequences not only for the differential diagnosis of pathologies of the outer and inner retina, but also on the functional testing of retinal implants. This article gives an overview of the current state of knowledge.