Did you find out the cause of this problem? From the pictures it looks as though my pit has the same problem and I am very curious as to what caused your pit's problem. I've brought mine to the vet 4-5 times and my girlfriend and I are still seeing the same problem.
try using some saline to flush out the eye a couple time per day. cheap saline from target or walmart is only a couple bucks. the kind for contact lenses. sometimes comes in a 2 pack.
squeeze the bottle and make the stream go from the inside corner of the eye toward his temple/cheek. this will prevent anything from going down his tear ducts. get all the gunk out and flush one more time.
apply the medication after you rinse the eye.