I had simliar problems last year. I found a practive area where I could practive out to 150yds. I used a laser to mark off every 10 yrads starting for 40-100 and just learned the feel for each distance. After getting comfortable I would hit 1 shot from each yardage until every shot was inside 15ft. It took about 2 hours 3 times a week for 2 weeks to geet everything dialed in but I havent had a problem since.

Just distance only? 

You may want to consider swinging more conservative - the goal of wedge shots is getting on target  and not trying to knock the snot out of it.   The other benefit of swinging conservative is you have better distance control (you aren't falling on your keyster when choking down).   You also want to maintain a constant swing speed or tempo regardless. 

Here's a rule of thumb - on a full swing you reduce distance by 10 yards for every 1/2" you choke down (this is for both full square stance swings and full swing pitches).   It is 5 yards per for 1/2 swings and 2.5 yards for 1/4 swing and chip shots.

To give an idea of distance - I hit a full swing PW about 110, 80 yards for a full pitch, about 50 for 1/2 swing pitch and about 30 for 1/4 swing.  I hit a 50 wedge ~95-100, full pitch about 65, 1/2 swing pitch about 40, 1/4 swing about 25.   MY 54 is 80 yd for full shot, 50 for pitch, 35 for 1/2 swing pitch and 25 for 1/4 swing.  I hit about 65-70 for full swing on the 60 (40 for full pitch, 25 for 1/2 swing pitch and 15 for 1/4 swing).  

I generally don't take a full swing with the Vokeys (except maybe the 50) and then it is about an 80 percent effort.  My most effective pitch shots are the 1/2 swing and 1/4 swing. 

Also may want to consider using the 7-9 irons in the pitching mix.  They come in handy when hitting in windy conditions or hitting uphill to a 2 tiered green with the pin in the back (my go to shot from 65 yards in this case is a 1/2 swing pitch with a 9 iron).   Also work when you just get plain lazy or the "all of a sudden swing glitch" shows up (for instance, pitching with an 8 iron from 100 yards instead of a full swing with a gap wedge).