Are extra/spare vision devices considered critical survival items? I guess they could be if you were seriously near sighted and as was mentioned they could be critical in reading a map; but is the map itself a critical survival item? I imagine that depends on the definition of critical.

I have a magnifying glass to use for reading maps and other things. I use off the shelf 1.25 reading glasses and sometimes they aren't quite enough for the small print.

The question for this thread is that if there is a significant space limitation, do reading glasses have a high enough priority to bump something else out? Are the glasses critical or nice to have?