I don't think that link to "ab oculis" is relevant. I suspect that "ab" just means something like "on, in front of" in this case: "glasses in front of the eyes

I don't think that link to "ab oculis" is relevant. I suspect that "ab" just means something like "on, in front of" in this case: "glasses in front of the eyes for reading". If you have time, check this article for the various possible meanings of "ab": http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0059:entry=ab http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:19... (It's a bit more detailed than wiktionary!)