The invention relates to a method for highly accurate determining of a pupil diameter of an eye, using a camera system for spatial capturing of objects, the method including: imaging stereoscopic capturing of an eye region, wherein for an eye of the eye region a first and a second stereoscopic image arise. For each of the two stereoscopic images the method further includes: Transferring of the captured eye region into a color space. Determining of a region, within the captured eye region, as a region within a pupil of the captured eye region. Determining of a closed outer edge of the region within the pupil. Iterative determining of a closed outer pupil edge. The invention further relates to a corresponding device.
