A high intensity discharge light source includes an arc tube having a longitudinal axis and discharge chamber formed therein. The light source includes first and second electrodes having inner terminal ends spaced from one another along the longitudinal axis. Each electrode extends at least partially into the discharge chamber. The discharge chamber is deformed so that its internal geometry is substantially rotationally asymmetric about its longitudinal axis, and is substantially mirror-symmetric relative to a plane spanned by the longitudinal axis and by another transverse axis that is perpendicular to the longitudinal axis and is vertical in a horizontal arc tube orientation, as well as substantially mirror-symmetric relative to a central plane perpendicular to the longitudinal axis. In a preferred embodiment of the disclosure the discharge lamp is of a single ended construction and the arc tube of the lamp is of double ended configuration, the discharge lamp having proximal and distal end electric lead wires to connect the arc tube to the lamp base, and the distal end electric lead wire is running below and parallel to the longitudinal discharge chamber axis in a horizontal lamp orientation, and its lateral direction coincides with the lateral direction of the central convex portion of the laterally complex concave-convex-concave deformed surface portion all along the longitudinal axis of the discharge chamber.