A device and process for determining the dominant eye of a patient (10), wherein the device includes a target (120), a camera (110) for acquiring an image of the patients face, and a mask (200) to be positioned in front of the patients face. The mask includes a closure face (210) suitable for hiding the target from the patient while enabling the camera to see the patients face, and a viewing window (220) for the patient to view the target and which is located through the closure face in order to enable the patient to view the target with only one of his two eyes.
