Absolutely Carolyn - That's Allergies! I am not sure where you are seeing that this isn't a common issue in the breed, since actually, it is. Allergies are an immune issue - and anything immune related is very common in Berners.
On my NaturalBerner list, I would say that 90% of the folks that come to join do so because of the severe allergies or GI Tract issues they are experiencing. I see everything from immune systems so hypersensitive (the definition of allergies) that they are pulling their hair out, and clawing their eyes raw to very mild immune responses involving congestion and red eyes.
Your guess about the trigger - environmental - is probably accurate. But I see so many Berners with allergies because as I have posted before, we vaccinate them far more than they can handle and it is the vaccines that initially heighten the immune response (they are designed to stimulate the immune system) so far that the system starts over-reacting to everything. Its a fragile thing.
The best treatments that I have seen work in the breed include chinese herbs, homeopathy, a natural diet to strengthen digestion (70% of the immune system is in the GI Tract), and a few supplements such as BHI Allergy (homeopathic) and Beta-Thym...sometimes Quercitin helps, as does wild salmon oil for its anti-inflammatory benefits.
You can get natural eye drops - such as Similasan or Boiron to put in her eyes before she goes out, to soothe and help keep her from irritating them. Watch out for further symptoms however including congestion, the "gulps", itching, gunky ears, paw licking, and face rubbing.
Good luck!