Louise, like many other pugs, is troubled by her eyes. They have a cloudy film and she tends to get a lot of 'eye boogers.' This causes her to rub her eyes a lot. We took her in to the vet for a checkup, and he noted that she has eyelashes growing under her eyelids. (I know, eww gross. But again, it is apparently common with this breed.) This was obviously contributing to the cloudiness, or scarring on her eyes. At the time, we didn't take the diagnosis any further than that, as the cited option was surgery.
Friends showed us some information on a condition called Dry Eye that affects many dogs (and cats too) that had similar symptoms. Some more detailed information about this disease, and a possible treatment can be found here. Another site has a lot of specific information about symptoms, treatments and the importance of tears in the eye.
We contacted our vet, and are now armed with a prescription for Optimmune. Even if this doesn't cure Louise's condition, it will ease her discomfort by adding lubrication to the eyes. After having her on it for a week or two now, we can see a difference in the clarity of her eyes, and she does seem to be less troubled by them. Only time will tell if Louise's tear production will resume, or if this will be an ongoing treatment. Either way, I want to send sincere thanks out to Roxanne for looking out for our little girl.