Thanks for the answer, thing is, last year I had -1.50 or -1.75 (can't remember correctly anymore) so I was 'safe', now with my recheck I will have gone out of these limits by half a point in a bit more than a year (which I would contribute to a bit of eye strain due to some fatigue, and loooong time spent behind the books everyday, staring at books for a long time can also hurt your eyes. The fact that I went out of the -2 and then immediately a decrease of -0.5 dioptres is what's worrying me now... Anyway, this is already giving me some good hope.