The invention is related to a device for measuring a thickness of a component of an eye under test of a subject, said device comprising a frame (100) mountable on a user's head and an OCT photonic module (201), wherein said OCT photonic module (201) is attached to said frame (100) to permit an OCT probe beam of the OCT photonic module (201) to enter said eye under test； the device further comprising a light emitting diode (710) configured to emit an additional visible fixation beam (712), a dichroic mirror (708) arranged to collimate said visible fixation beam (712), and to combine and make collinear said visible fixation beam (712) with the OCT probe beam (205) to form a co-propagating collinear visible fixation beam and OCT probe beam (714), the device further comprising an angularly adjustable turning mirror (111, 113) configured to direct the co-propagating collinear visible fixation beam and OCT probe beam (714) into the eye under test； wherein the angularly adjustable turning mirror (111, 113) is dynamically controlled such that, when said light emitting diode (710) is turned on for a first period of time, said angularly adjustable turning mirror (111, 113) is oriented in a fixation direction wherein fixation is achieved by the subject looking at the visible fixation beam (712), and, when the light emitting diode (710) is turned off, the angularly adjustable turning mirror (111, 113) is oriented to direct the OCT probe beam (205) in the direction from which depth scan information is desired. A corresponding method of measuring a thickness of a component of an eye under test is also disclosed.L'invention concerne un système et un procédé pour obtenir des mesures ophtalmiques, le dispositif de l'invention étant conçu pour être monté sur la tête, automatiquement aligné axialement sur la longueur sur une cible sélectionnée et latéralement aligné de telle sorte que une source de TCO entre par la pupille de l'œil à tester. Le bâti de la TCO pouvant être montée sur l
