An OCT system comprises an OCT scan module for retinal scanning and an add-on anterior segment scanning module which includes at least one anterior segment scan lens (11) and an add-on fixation target (15) which is used to maintain the viewing direction of the eye (6) under investigation while achieving anterior segment scanning. Because the anterior segment scan module added to the exterior of an existing OCT system for retinal scanning has an add-on fixation target (15), it is possible to maintain the viewing direction of the eye (6) under investigation while carrying out anterior segment scanning without adjusting the internal beam path of the OCT system, and the OCT system of the present invention can be adapted to patients with only one functioning eye.