In theory, yes, any convex lens will concentrate light, but not all reading glasses will concentrate it sufficiently to generate pinpoints of heat. I remember, years ago, trying to do so with my mother's reading glasses; the best I could get was a circle of light about 1/2 inch in diameter (IIRC - it was many years ago). <br><br>I've also read that regular (concave) glasses can be used, if you hold them horizontally and pour a small pool of water into one lens; this should convert the concave glass or plastic lens into a convex combination glass and water lens. I've tried to do this from time to time, without any success. Possibly at my latitude (Calgary Alberta) the sun's rays are slanted too much; come to think of it, I'd likely have the same trouble using any convex lens that had to be held horizontal. <br><br>As far as I know, the only television "survivor" so far to have started a fire without matches was the school teacher (and ex-Air Force survival instructor) in season 1, who successfully used a fellow "castaway's" reading glasses to do it. (I quit watching the show shortly after she was "voted off"; it became clear that the show was more about office politics than wilderness survival, and I deal with office politics every day; why would I want to watch it for entertainment? :-)