Disclosed is a method for collecting data when a patient is subjected to a visual test involving line returns by the patient. The method includes: subjecting the patient to the visual test； recording the eye movements of the patient during the test； determining, in the records obtained, return saccades that make up line returns； calculating return saccade parameters from the records that correspond to the determined return saccades. The parameters can include an average number of saccades over a plurality of line returns, an average of ratios over the plurality of line returns, each ratio corresponding to the ratio between the amplitude of the first time-based return saccade in the line return and the total amplitude of the return saccades forming the same line return. The method is useful for diagnosing an oculomotor disorder that is involved in dyslexia.
