While Glaucoma is an extremely serious illness, it does not usually happen in dogs too much. Most of the time blindness in dogs happens from an accident, although there are those moments when Glaucoma happens due to genetic issues. When genetics are the cause, this is called primary Glaucoma. There are some breeds that are more genetically inclinated to catch Glaucoma, but a dog can get it because of eye disease, cataracts, cancer, or even eye infection. When it is caused by any of these issues it will be considered secondary Glaucoma. If dogs get Glaucoma, they can go blind quite quicklyly. Care should be given if you notice any of these issues.
Most of the time a dog will get Glaucoma in just one eye. The pressure comes from the aqueous humor fluid that is being built up constantly in the front part of the eye. When this happens the dog will eventually lose sight in that eye, but will adjust to seeing with the good eye. Because of this, it is difficult for the owner to realize the dog is having sight issues as they are still getting around quite well. This will also cause the dog pain, which they have no way of telling you about.
When a dog has been diagnosed with Glaucoma it becomes much harder to treat than if contracted by a human. Humans will take eye drops to help relieve the pressure whereas dogs have a hard time squeezing the bottle, so you have to do it for them. If you have never tried to give a dog eye drops before, it can be quite a difficult feat. Because of this, surgery will more than likely be required to release the pressure. Unfortunately, up to one third of dogs will have to have more than one surgery for their Glaucoma issues.
While Glaucoma in dogs is rarely detected before it's too late, there are ways of catching it before it's too serious. If you notice your dog favoring one eye, or see it constantly watering, you should check with your vet. If your vet catches the Glaucoma before it gets too serious, there is a good chance that your dog will only require one surgery. While your dog has no way of telling you that their eyes are bothering them, you have to be on your toes and check from time to time on your own.