It's hard to say. These dogs ARE prone to allergies. I would go ahead and pick up some sterile saline (like used to lubricate human eyes, not the medicated contact solution) and use it twice daily for the next few days. If it's an allergy, this will help. If there's a foreign body in the eye, this will help flush that out as well.
Then see your vet if you still don't start to see some improvement.
Let me know if you still have questions.
