Only practice brings about any major changes in how people react to or conceptualize the world -- which I suppose is roughly what we mean by human consciousness. Reading a roll is a profoundly different _practice_ than reading a codex. Reading an e-mail message or reading a facebook, or reading in a printed codx (book) rather than in a handcopied book does not constitujte a fundamentally different way of arranging knowledge. One can browse in a codex, but not in a role. One can flip back in forth the pages of a codex, but that can't be done with a roll. Besides browsing, one can also INDEX a codex. It took a number of centuries however before this feature of the codex was realized. (Printed books were a precondition here.) And the early encyclopedials were not alphabetized. But to arrange material alphabetically, a gain, leads to another way of conceptualizing the world -- print in itself does not have that effect. (It was the quantity of handbills or books that could be produced, not the fact that that they were printed, that made a significant difference politically and culturally.
When my eyesight began to fail, the most immediate impact was that I was no longer able to browse in texts or use an index. When the optilex still allowed me to (sort of ) read a page, I tried several times to continue and earlier study by using the index of a work crucial to that study. I labored away off and on for several weeks, then gave it up. You don't realize how crucial browsing is to thought until you lose that capacity. There is technology to turn text to speech, but that expericnes rather resembles the experience of reading a roll: one simply cannot easily and quickly flip back and forth.
Carrol