Red eyes and discharge from them

Our springer has been dealing with an eye infection or allergies since early summer. I have seen 2 different vets and spent quite a bit of money. The first one thought it was conjunctivitis and gave pills and eye drops. Nothing has cleared it up. It improves sometimes, but then gets bad again. She does not spend a lot of time outside except when I walk her. I am hoping it will clear up with the cold weather but I also don’t want her to have any permanent damage if I let it be for a while longer. Anyone have eye problems with your springer?