Unfortunately, alot of people think their eyesight gets worse each year-- but think about it; if that were the case 1) Everyone over the age of 30 would be blind, and 2) We wouldn't need to get your glasses/contacts changed because everyone would have the same prescription, (the thickest we could possibly make) and everyone would have that.
Look, a prescription is not linear-- meaning a "4" does not mean that it is "worse" than a "3". It is much closer to a set of coordinates in 3 dimensions. Knowing that, let me ask you: do the coordinates 2,4,7 seem "worse" than a 1,5,3?! I know that you can't answer that and that is EXACTLY my point.
But to answer your question -- there have been studies that show, by wearing rigid contact lenses you can decrease the progression of your myopia by a third. There was also a recent study suggesting that it might be possible to get similar results by using high prescription silicone soft lenses by wearing them inside out and only at night.
All of these results depend on your prescription, family history, sex, and age.
I've been a licensed optometrist for 16 years.....AND I did stay at a Holiday Inn Express last night.