I started having problems with my left eye about 15 years ago.  My left cornea had rapidly changing it's shape over the space of 2 - 4 months.  My eye doctor examined me and saw a change in my eye's topography, and noticed a thinning in my cornea.  An update in my Rx returned my eyesight to something near normal for about 6 months, when my cornea changed again.  I've battled this on and off for 15 years now; sometimes my vision gets worse, meaning I become more nearsighted; sometimes my vision IMPROVES, meaning I become LESS nearsighted.  Does this mean my both cornea is both thinning and thickening?  Is that normal for keratoconus?