A method of assessing a presence and/or severity of at least one of diplopia and convergence insufficiency disorder of a patient； it includes providing a patient with an image pair configured to present a first image to a first eye of the patient and a second image to a second eye of the patient； obtaining performance information of the patient when the patient performs a task requiring the perceiving of the information content of the first image and the information content of the second image； adjusting, based on the performance information, the difference of the at least one image parameter between the first image and the second image； and assessing the degree of at least one of the diplopia and convergence insufficiency disorder of the patient based on performance information of the patient when the patient performs the task following the adjusting.
