Is 20/30 vision better or worse than 20/20 vision - serious replies only please.?

For years I was told I had better than 20/20 vision. For the past few years I having been getting signs of slight nearsightedness. My ophthalmologist told me the other day that I have 20/30 vision (I am blind in the other eye), so I don't know if I still have great vision and it has simply declined slightly or if it less than perfect now. Anyone out there really know? Thanks so much!