Cataracts are any opaque spot on the lens of the eye, causing at least some loss of vision. Some cataracts are hereditary and some are not. Surgery may help the dog recover some vision. Ulcers on the eye are most often caused by an intital scratch or injury. They must receive immmediate attention or there will be some loss of sight.
Ulcers require a vet's attention to determine the best way to proceed with treatment.
Some lines of pugs can go through life without an eye problem, while others have chronic problems. A double row of eyelashes, normally on lower eye, that works much the same way to irritate the eye that is seen in Entropion. Again, surgery is called for because it causes the dog to be very uncomfortable and can go blind. Dogs with dry eye normally do not have shiney, glistening eyes, but rather have dull and rough-looking eyes. It is caused by the lack of tear production in the eye - either the nerves have failed to stimulate the tear glands, or the tear glands are no longer working, or the ducts that carry the tears to the eyes are blocked.