Hi Jeffrey! I noticed you posted this several days ago, but wanted to share this with you since it sounds like your pet suffers from eye discharges frequently. Have you tried going with an old and natural way to do it? I am talking about CHAMOMILE TEA BAGS!
I used to have a cat, who would have a cat litter every so often, and from time to time I would find her kitties with eye discharges, to the point that their little eyes would almost get glued! (This could develop overnight.) Obviously, I would freak out and wanted to take them to the vet immediately.
My mother, a great home natural-remedy woman, who learn a lot about it because of having 5 kids and a limited budget, told me just to make a cup of chamomile tea and once the tea was warm, to clean their eyes with a soft cloth as often as I could through the day (at least every time you see the eye discharge is adding up). Within a couple of days I would see tremendous improvement, and by the third day they would be just fine. Just to name a few of Chamomile's healing properties it works as a anti inflammatory, anti microbial, allergy natural relieve remedy.
If you like to give it a try, I would suggest you to not rub to hard since you might damage the retina (specially if the discharge is already crusty-hardened). Just continue cleaning your pet's eye until it's gone. Sometimes, it can take you 3 try's to get the discharge to soften but it's better to be patient, than to cause more discomfort to your pet than they are already in. More recently, (and so you also know I not only tried this natural remedy with cats) I had my dog wake up one day with a crusty eye. I made some tea, and cleaned his eyes through the next couple of days (even when his eye cleared the first day, I continued cleaning his eyes the next day to make sure he was fine.) and Voila!! All good!!
Even when it's always good to have a Vet look at it, maybe before you book an appointment you can try this home remedy for a couple of days, and if there is no improvement then take them to the Vet. Whatever gives you peace of mind!
P.S Even when it seems they only have eye discharge in one eye, I would always clean both eyes to ensure and prevent the second eye getting it too! Good luck!!!