Blue eyes in older dogs may be caused by eye disease, liver disease, pigmentation, etc. Generally, this will happen to older dogs. It is best to take the dog to the hospital for examination. Conjunctivitis, keratitis, and cataracts will all turn your dog's eyes blue and require timely treatment, otherwise they may affect vision. Pay attention to keeping the eyes clean, and remove foreign objects promptly. Eat a light diet and avoid too much salt. Causes increased eye discharge in dogs.