Check your dog's eyes as part of your regular grooming routine to stay on top of any problems.

One of the prominent problems with a Japanese chin's eye is tear stains. In most animals tears are constantly produced and drain through the small ducts in the eyelids and then through the nose. (And that's why your nose runs when you cry.) Chin's eyes are prone to weeping, that is, they overflow because of excess tearing. The prominent eyes stretch the eyelids and cut off the drainage system. Blocked tear ducts also cause tearing but chins will have trouble with tear stains because of their protruding eyes. Tear stains are the result of normal bacteria on the hair and skin reacting to the clear tears. You can buy good tear stain removers. Some of removers have bleaching agents in them, so read the directions carefully. You don't want to use a remover that whitens hair on your chin's black hair.

Hair also draws tears out of the eye. Take a blunt nosed scissors and cut off any offending hairs, taking care to cut parallel to the edge of the eyelid. A stray particle, an allergy, or abnormal eyelid or eyelash turned inward and rubbing against the eye can cause tearing also. Keep your dog's eyes clean of any mucus to prevent infections. Mucus is a great breeding ground for bacteria and the bacteria often migrates into the eye.

Cataracts: a cataract is an opacity within a dog's lens. A cataract can be very small and not interfere with vision at all, an incipient cataract. An immature cataract involves more of the lens and is a visible cloudy dot on the eyeball and causes blurred vision. The entire lens will eventually become cloudy and all functional vision lost, this is a mature cataract. Most times cataracts are inherited and show up in a few weeks or as the dog gets older. Diabetic dogs also have problems with cataracts as do older dogs. Treatment of cataracts often involves surgery to remove the cataract, take your dog to the vet if you start seeing signs of cataracts.