Don't know all that much but I do know it is a very painful condition and removing the eye is usually the only option. If he is sometimes closing his eye I would think that the dog is indeed in pain. I had a guinea pig once with gloucoma, common with guinea pigs, and I did have to have the eye removed. If they have not already they should be consulting with an veterinary opthamologist.
Glaucoma is not uncommon in PBGVs. Typically when diagnosed they start the meds to try and reduce the pressure. If that does not work, then removing the affected eye is recommended. Pretty standard recommendations for the disease. A Vet Opthal should be consulted.
Julia
Had a similar problem with my 10yr.old girl. She had glaucoma symptons, took her to an opthamologist and it was a melanoma. She had the eye removed and is doing great.
