An optical assembly (1) includes an optical element (2), a mount (3) configured to hold the optical element (2), and a plurality of fastening elements (12) with fastening areas (14) configured to fasten the optical element (2) to the mount (3). The fastening elements (12) bridge an interstice (11) between the optical element (2) and the mount (3), and a purge device (15) produces at least one purge gas flow (16) in the region of the optical element (2) such that the purge gas flow flows around the fastening areas (14) of the fastening elements (12).