A device for determining the dominant eye of a patient, characterized in that it comprises: - a target visible by the patient in a measuring position; - acquisition means for acquiring an image of the face of the patient in the measuring position; and - a mask to be positioned between, on the one hand, the face of the patient in the measuring position, and on the other hand, the target and the acquisition means, comprising: a) an obstructing panel: a1) that has dimensions such that it is capable of being interposed between the target and the two eyes of the patient in the measuring position; a2) that is able to transmit only at most some of the light propagating from the target toward the patient in order to hide the target from the patient in the measuring position; and a3) that is able to transmit at least some of the light propagating from the patient toward the acquisition means in order to allow the acquisition means to acquire an image of the face of the patient in the measuring position, said image being enough to deduce which of the two eyes of the patient is his dominant eye; and b) a sighting window used by the patient to sight the target: b1) that is located in the obstructing panel; b2) that is able to transmit the light propagating from the target toward the patient, in order to allow the patient to sight the target; and b3) that has dimensions such that the target is visible only by a single eye of the patient in the measuring position. - a target visible by the patient in a measuring position; - acquisition means for acquiring an image of the face of the patient in the measuring position; and - a mask to be positioned between, on the one hand, the face of the patient in the measuring position, and on the other hand, the target and the acquisition means, comprising: a) an obstructing panel: a1) that has dimensions such that it is capable of being interposed between the target and the two eyes of the patient in the measuring position; a2) that is able to transmit only at most some of the light propagating from the target toward the patient in order to hide the target from the patient in the measuring position; and a3) that is able to transmit at least some of the light propagating from the patient toward the acquisition means in order to allow the acquisition means to acquire an image of the face of the patient in the measuring position, said image being enough to deduce which of the two eyes of the patient is his dominant eye; and b) a sighting window used by the patient to sight the target: b1) that is located in the obstructing panel; b2) that is able to transmit the light propagating from the target toward the patient, in order to allow the patient to sight the target; and b3) that has dimensions such that the target is visible only by a single eye of the patient in the measuring position. a) an obstructing panel: a1) that has dimensions such that it is capable of being interposed between the target and the two eyes of the patient in the measuring position; a2) that is able to transmit only at most some of the light propagating from the target toward the patient in order to hide the target from the patient in the measuring position; and a3) that is able to transmit at least some of the light propagating from the patient toward the acquisition means in order to allow the acquisition means to acquire an image of the face of the patient in the measuring position, said image being enough to deduce which of the two eyes of the patient is his dominant eye; and a1) that has dimensions such that it is capable of being interposed between the target and the two eyes of the patient in the measuring position; a2) that is able to transmit only at most some of the light propagating from the target toward the patient in order to hide the target from the patient in the measuring position; and a3) that is able to transmit at least some of the light propagating from the patient toward the acquisition means in order to allow the acquisition means to acquire an image of the face of the patient in the measuring position, said image being enough to deduce which of the two eyes of the patient is his dominant eye; and b) a sighting window used by the patient to sight the target: b1) that is located in the obstructing panel; b2) that is able to transmit the light propagating from the target toward the patient, in order to allow the patient to sight the target; and b3) that has dimensions such that the target is visible only by a single eye of the patient in the measuring position. b1) that is located in the obstructing panel; b2) that is able to transmit the light propagating from the target toward the patient, in order to allow the patient to sight the target; and b3) that has dimensions such that the target is visible only by a single eye of the patient in the measuring position.