Further studies by Christoph Scheiner concerning the optics of the eye.

The physician, mathematician and astronomer was born in 1573 in Wald near Mindelheim in Swabia, Germany. He died in 1650 in Neisse in Silesia. He discovered the sun spots and also dealt with the physiological optics of the eye. Further observations of Scheiner's are represented, i.e. from his books Oculus and Rosa Ursina, concerning the anatomy of the eye, the crossing of the beams through a small opening (Camera obscura), stenopeic effect, proof that the crossing of the visual beams takes place in the eye, description of the cataract and its treatment, Christoph Scheiner's eye model, the visual angle, the rotational centre of the eye, the comparison of the optics of the eye and the telescope.