Can I have a touch up after 3.5 years of having PRK to reduce/eliminate astigmatism?

I had PRK 3.5 years ago, 6 months after the surgery I ended up with OD Sphere -0.25 / Cyl -0.5 and OS Sphere 0.0 / Cyl -0.5 I was able to see better than before but not 20/20, my doctor said that it wasn't recommendable to do a touch up with those numbers, now I feel that my right eye is way better than what it was but the left eye is worst, is so bad that if I cover my right eye I'm not able to read the screen on my desk. I've gained 20 lbs , I don't know if that affects something.