[souffle]

The eye problem in our case was due to an infection causing changes like scarring and degeneration of the tissue in the tear glands and ducts. I guess it is a bit like chronic sinusitis in humans. You can't do anything to avoid except what you are already doing in avoiding allergens but bacterial infections can come from anywhere and are much more likely to flare up in a hamster with a weakened immune system due to an issue elsewhere. I would ask the vet to do a urine test to check for diabetes.