Discharge and Crust in One Eye, Vet Said They Saw No Real Source

Freddie is my 1 year old big orange tabby. A couple of months ago he started blinking one eye a lot and soon enough clear fluid started coming out. I took him to the vet but the vet said he didn't see any cause for it, prescribed some eye drops, and sent us on our way. The eye drops don't seem to make a difference and now there is brown crust forming in the inner corner of his eye by his nose. I plan to take him back to the vet as soon as my wedding on Saturday passes. So next Monday. He doesn't seem uncomfortable, in pain, or lethargic. He acts like usual self aside from the winking, fluid, and crust in his left eye. Does anyone have any idea what it could be? I know I must seem like a worry wart but I've had him since he was 8 weeks old. Keeping him healthy and happy is important to me. Any advice or wisdom is welcome!

A vet visit should be on the list.  He may be experiencing seasonal allergies.  Have you heard him sneeze at all or is is just the eye? 

I have a cat that had Herpes Upper Respiratory infection when he was a kitten.  He was left with one eye that constantly tears, drains and crusts.  I have him on a supplement to help boost his immune system.  I also take warm cotton balls and gently remove the draining fluid and any built up crust.  You can do this multiple times each day until you get to the vet.

Best of luck on your wedding day!!

Thank you for your reply. I'm going to swab his eye as per your recommendation. When I go to the vet on Monday I'll be sure to ask about allergies and supplements like you mentioned. No sneezing or anything like that. He really acts perfectly normal aside from the winking, liquid, and brown crust. Hopefully Monday the vet will find a better solution. 

And thank you for the good luck wish! I am very excited about it, though still a bit worried for my little buddy.

the supplement is probably L-Lysine.  Many, many people here use it for their kitties.