Open Question: Why are my goggles so foggy?

I have been swimming for about 9 years and I just got new goggles last week and they are already getting foggy after about 25 yards. Its really annoying. I got some antifog spray but its not really helping me. My goggles also have a prescription on them so i can see good in them (I have bad eyesight). What can I do so they dont fog up all the time??