Never dealt with it in cattle, but have dealt with it in horses. The treatment was almost the same.
There's a horse where I work that has chronic uveitis, in that she has 'flare-ups'. She is on aspirin therapy, one dose a day as a preventative and is has made a big difference. However I would think that preventive would not be applied to cattle.
The flare-up treatments she recieves,(similar to your cow) does help, and does clear things up in about a week or so.
Good luck.
Katherine