Screen magnifiers take a small section of the screen and magnifies it. More complex that that of course, mouse tracking, when a dialog pops up must track to that forms and so on. Users of this software do not require much in the way of different presentation, but as the enlargement gets greater, toward 8X it becomes impractical, too small an area of the screen, users move toward speech or braille output.
Braille displays are rare due to the expense, around $12000 for a 40 character display. Braille print is cumbersome but necessary, we also make use of audio recordings for instruction.
Screen review apps rely on text output
Can run a demo of jaws if people are interested