Definitely try to see a veterinary ophthalmologist. They will be able to pinpoint things a regular vet (even a very good one) will miss.
I have had two greyhounds with pannus. With Tipper, I caught it very early, and what started out as twice-daily eyedrops are now a very easy maintenance level of twice weekly, as prescribed by the ophthalmologist. Tip's visible symptoms decreased to the point where a regular vet can't even tell he has pannus anymore. And yes, if it shows up in one eye, it is possible for it to show up in the other down the road. But do not treat until diagnosed.