Audio-impaired users are covered by text-only versions of the class. Visually-impaired are partially covered by the audio versions of the classes. However, the quizzes and exercises do not have an audio component. With federal regulations requiring accessible hardware and software, your classes not supporting screen readers is a big thorn in our side. I suggest that you either make your system support screen readers, that you furnish an option for the questions and exercises to be audio-only, or that you provide different exercises for the visually-impaired.