SUBSORDIG analyses the subtitling parameters currently used on the Spanish audiovisual market, and, more specifically, compares these subtitling parameters to the different subtitling conventions adopted in other European countries. All the data analysed in the SUBSORDIG project were obtained from detailed interviews with different groups of users and answers provided by these groups in questionnaires, following a bottom-up methodology. Results from the project reveal tendencies that might question the validity of these data. These tendencies are the result of the possible influence of local subtitle conventions on individuals’ reading habits and, consequently, on the individuals’ subtitling preferences. In order to remove any subjective information from our study, it was essential to adopt scientific tools such as eye-tracking technologies, which are currently used in other disciplines such as psychology, marketing and medicine, to enable further studies based on objective analysis, and to provide a basis for comparison and proper definition of the technical aspects involved in subtitling. This contribution describes the application of eye-tracking to the study of subtitling and focuses on the steps taken to evaluate and to update many of the technical parameters involved in the process.