My Nicky, 11, has had 1 deep ulceration and another large but shallow ulceration in the last year. Both have healed, slowly, but we will most likely need to use eye drops and ointment probably forever. Her eye's tear production is only slightly low, but I flush her eyes after the dog park, and usually use ointment at night . Her animal ophthamologist is an amazing man, he does all these terrible things to her eyes just talking to her and petting her! He told me he went to a seminar last year and they discussed corneal ulcerations and said that 2 breeds in particular seem to heal slower than others, one of those breeds was basenji. They do eventually heal, but slowly, for no particular reason.
He gives me "Tears Again" liquid gel for eye drops, it is thicker than most of the eye drops, and plain old puralube ointment. (We used antibiotic ointment for the first month or so).
Fortunately both eyes have healed and her vision seems to be fine. Good luck with Buster!
Oh, the instruction my vet gave me is to put just the tip of the ointment-tube in hot water for about 10 seconds, it melts what's in the tip and it just drops into the eye and spreads out, much more comfortable for the dog than squeezing a big glop of goo into the eye. I gave myself a small corneal abrasion last week and tired both methods of using ointment and the warm, liquified stuff was like liquid velvet on my painful eye, so I can say firsthand that it is worth the extra effort!