You notice a crusty buildup in the corner of your dog's eye during your morning walk. Yesterday it was clear and watery. Today it's yellowish-green. Should you worry, or is this just part of normal eye function?
Dog eyes produce discharge for dozens of reasons—some completely harmless, others signaling conditions that could threaten vision if left untreated. The color, consistency, and accompanying symptoms tell you whether you're dealing with a minor annoyance or a veterinary emergency.
Every dog produces tears constantly. The lacrimal glands above each eye secrete a three-layer film that lubricates the cornea, delivers oxygen and nutrients, and washes away debris. This tear film drains through two tiny openings called puncta, located in the inner corner of each eyelid, then travels down the nasolacrimal duct into the nasal cavity.
When this system works perfectly, you'll see minimal discharge—perhaps a small amount of clear or slightly whitish material in the morning after your dog's eyes have been closed for hours. This dried tear residue is the canine equivalent of "sleep" in human eyes.
Is eye discharge normal in dogs? Yes, to a degree. A small amount of clear or light-colored discharge that doesn't cause redness, squinting, or behavior changes falls within normal parameters. Many dogs wake up with dried tearstains or small crusty deposits that wipe away easily.
Problems arise when discharge becomes excessive, changes ...