The present invention relates to compounds of formula wherein R1, R2, R3 and R4 are as defined in the description and claims, and pharmaceutically acceptable salts thereof, for use as therapeutically active substances. An aberration control optical system is operable to produce an image aberration, and an aperture stop is operable to limit a light beam passing through the aberration control optical system. The invention further relates to corn seeds and plants produced by crossing plants of variety CV032767 with plants of another variety, such as another inbred line. Thereafter, a sensor in the camera is enabled to receive an image, and simultaneously, it is determined whether the image satisfies the composition profile.