Discharge that can be part of a normal eye
Eyes clean themselves with tears, and a little clear wetness at the inner corner, or a small dry crust after sleep, is common — especially in breeds with prominent eyes or shallow tear drainage, and in windy weather or dusty fields that make eyes water briefly. If the eye itself looks bright, white where it should be white, fully open, and your dog is not rubbing it, gentle wiping with a clean damp cloth and watching is usually reasonable.
Use a separate clean area of the cloth for each eye, wipe away from the eye, and do not share cloths between dogs. If the amount is creeping up day by day even without dramatic signs, that trend itself earns a routine appointment.
Discharge that should be seen promptly
Yellow or green, thick, or sticky discharge that glues the lids, returns quickly after wiping, or affects one eye much more than the other suggests infection or significant irritation and should be examined. The same applies to discharge with redness of the white of the eye, a hazy or blue-grey cloudiness on the surface, visible swelling of the lids or the pink tissue at the corner, or discharge starting suddenly after a walk in long grass, a scuffle, or a bang to the head.
Do not be reassured just because your dog is eating and wagging. Eye problems, including scratches and ulcers on the surface, are painful and can worsen over a short period while the rest of the dog seems fine.
Pain signs move an eye problem to same-day
Squinting, holding the eye closed, flinching from light, pawing or rubbing the face on furniture, head shyness on that side, or a dog who suddenly seems quiet and guards his head are pain signals, and a painful eye should be seen the same day. Prevent rubbing in the meantime — an inflatable or cone collar if you have one that fits — because a rubbing paw can turn a surface scratch into a deeper injury before you arrive.
Avoid putting anything into the eye that was not prescribed for this dog and this problem, including leftover drops from a previous episode. Similar-looking eye problems have different causes, and the wrong drop can make some of them worse.
What the vet needs to know
Tell the vet which eye, when the discharge started, its colour and amount, whether it followed exercise, grooming, or an injury, and whether your dog has had eye trouble before. Note any other signs at the same time — sneezing, a runny nose, reduced appetite — because eyes and upper airways sometimes flare together.
Breeds and individuals differ in how much watching an eye needs: dogs with prominent eyes, dogs who run through undergrowth, and dogs who have had an eye problem before all merit a lower threshold for calling. Check both eyes in good light each morning while discharge is present, comparing whiteness, openness, and comfort side to side, because the comparison often reveals a problem owner familiarity hides. If discharge is linked to seasonal walks through particular fields, note the route — that detail can matter when the vet considers irritation and allergy patterns.
Recording the affected eye, the discharge pattern, and any examination findings in KinsLe Pet Passport means a recurrence is compared with the last episode properly, eye by eye.