Hi Liliantay,
There are various causes of the red eyes in dogs. Allow us to cite some major causes of such veterinary medical cases.
1. Eye irritation, causes by chronic/constant irritation due to breed predisposition. In Shih Tzu, there is an occurence of distichia which is the abnormal growth of eye lashes. This may NOT cause ocular problems but in some cases in may cause eye surface irritations. We suggest to refer to your veterinarian to keep these lashes out of their eyes if this case is suspected.
2. Bacterial infections due to their Shih Tzu's protruding eyes, they may susceptible to injuries or trapped foreign objects resulting to bacterial infections. Medications under vet supervision are needed if this case is suspected.
3. "Cherry Eye", as Shih Tzu's are one the breeds that are predisposed to this condition. This is the protrusion of third eyelid in dogs, in cases you suspect this case, veterinary surgical option may be discussed with your veterinarian.
4. Others, thay may include respiratory problems. Watch for signs of "colds" or respiratory distress as it may also not just mucous discharges on the nose but also red eyes.
For treatment and cure, we suggest to refer to your veterinarian for appropriate treatment due to a wide range of possible causes. A clear diagnosis is a must for a more efficient and effective treatment mode.
For other related information, please visit and talk to our Pet Care Consultants in all our PLC outlets.
With best regards,
Eliezer M. Bauzon, DVM RN