Tyler Cowen on books that require extra-sharp eyes:
Marginal Revolution: Which are the books with the smallest print?: Editions of Dostoyevsky and Tolstoy often have excessively small print. Why? The major works by those authors are long. Larger print will make the volumes too long and thus too expensive. Perhaps more importantly the volumes will appear too forbidding to the average buyer. But isn't miniscule type for Raskolnikov hard to read? Ah... most of the people who buy the book don't read it. If miniscule type gets them to stop reading sooner rather than later, you might even call it a Pareto improvement.
Self-help books almost always have reasonably large print or even ridiculously large print. The author doesn't have much to say and the publisher wishes to pad the book so it looks real. Furthermore most self-help books are read (at least in part), so to keep the reader happy the print should be large.
Can you think of other generalizations?
Which books are most likely to go into "Large Print" editions?