The objective of this research is to build up specific knowledge on the needs of students with visual impairment in terms of accessibility of digital textbooks and possible solutions to meet them. More specifically, the aim is to study the specific characteristics of the modalities of access to digital textbooks and multimedia by these students and their consequences on the cognitive requirements associated with their processing in order to design and evaluate design principles.Several complementary studies have been carried out to analyse the needs of visually impaired students in terms of digital educational accessibility. Overall, the results indicate that blind students are currently unable to use digital textbooks for technical accessibility reasons. Even though visually impaired students can access digital textbooks and have a positive perception of them, in reality they rarely use them. This is due to difficulties related to the use of screen magnifying tools that do not easily accommodate the organization of information in a double-page format and the lack of multimodality. When carrying out tasks involving the digital textbook, the enlarged view imposes more navigation and more attentional sharing than their sighted peers. This mental demand generates an increase in extrinsic mental workload, and subsequently a greater number of dropouts, a deterioration in performance and longer completion times, compared with sighted students. To overcome this difficulty, a solution principle based on the principles of information integration and multimodality (Mayer, 2014) was evaluated experimentally. The results indicate benefits of the solution on goal attainment, completion time and performance measures, as well as on subjective perceptions, compared to the classical separate and unimodal format. These results make it possible to enrich both the research field of multimedia learning, which has given little consideration to the case of learners with disabilities, and to provide recommendations for the design of accessible digital textbooks.This research has received financial support from the « Université Fédérale de Toulouse Midi-Pyrénées », the Occitanie Region and the « Fondation Internationale de la Recherche Appliquée sur le Handicap ».