Runny eye/discharge?

Hey all! My boy Barkley has been having some runny eye issues and little eye boogers. I've been doing nothing differently, so I'm not sure what's causing it. I'll add imgur links because I'm on my phone and it won't let me attach images for some reason. I'm planning on calling the vet and making an appointment for this weekend, but if anyone has any idea what this is I would appreciate some insight. I know eye discharge is usually an awful sign, so I'm kind of freaking out.

Here's the imgur album,
http://ift.tt/2xpcczV