Hello my astigmatism has incresed in the past four years as in 2006 my prescription was as follows :right eye (-2,00 axe 15)-3,50 for left it was (-2,00 axe 170)-2,5 and the last prescription that i have just made this year 2010 shows (-2,75 axe 15)-3,50 for the right eye and (-2,50 axe 180) -2,5 for the left that meabs that my astigmatism increased is that normal? will my astigmatism worse with age ? can it get better with time ? thank you