Current interactive learning environments cannot be accessed by learners with disabilities, in particular for students with vision disabilities. Modeling techniques are necessary to map real-world experiences to virtual worlds by using 3D auditory representations of objects for blind people. In this paper, a model to design multimedia software for blind learners is presented. The model was validated with existing educational software for these users. We describe the modeling of the real world including cognitive usability testing tasks by considering not only the representation of the real world but also modeling the learner's knowledge of the virtual world. The software architecture is also described by using this model, displaying the components needed to impact learning. Finally, we analyze critical issues in designing software for learners with visual disabilities and propose some recommendations and guidelines.