1. A method of determining the spatial relationship of an eye ( 10 ) of a person with respect to a camera device ( 20 ) which provides images of the eye ( 10 ), characterized in that the method comprises: a model acquisition phase in which a customized model of the eye ( 10 ) is constructed and a reference spatial relationship of the eye model with respect to the camera device ( 20 ) is determined using a reference image of the eye ( 10 ); and a tracking phase in which position and/or rotation coordinates of the eye ( 10 ) are determined by aligning the eye model to a current image of the eye ( 10 ).