After wearing contacts for about 10 years, I had trouble with mine. It wasn't the same as yours, though. Mine felt dirty all the time, even if I had just taken them out in the morning. They did feel scratchy, though. I also had trouble keeping my eyes open--my eyes felt very tired. It took 3 weeks of going to the eye doctor on a weekly basis before the dr. and I figured out it was an allergic reaction to some mascara I had bought.
I don't know if any of this will help you, since our symptoms were different, and yours may not be an allergic reaction, but I also had a problem after I quit using the mascara. I could no longer use the multi-purpose contact lens solution. This was before they had the "no rub" solution, but I can't use that either (I've tried). It just wouldn't get my contacts clean. My dr. recommended Ao Sept disinfectant solution. It's a hydrogen peroxide-based contact lens solution, and I've found I can use any brand of that. If I run out of the disinfectant solution and use multi-purpose instead, in 2-3 days my lenses start feeling dirty and they start discoloring (turn yellow).
I don't know how that will help with lenses that slide around, but maybe trying a different kind of contact lens cleaning system will help??? You can get a store brand version of the hydrogen peroxide disinfectant for about $6-$7. It works as well as the name brand.
Edit: I've been using the hydrogen peroxide disinfectant for about 10 years now, and it works great. It makes my lenses last longer, too. My eye dr. is kind of ambivalent about that. He would probably prefer I not tell him how long I wear my lenses now!
Edited by gardening momma, 23 April 2009 - 03:40 PM.