I have -3.5 and -4.0 spherical and had it when I enlisted in 1988. My eyesight has not worsend in the last 16 years, and I passed my last physical in fine shape. I could never have been a pilot, but there were no other jobs limited to me because of my eyesight.
Red/Green color vision is also VERY important to the militay and will limit your job choices.