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.

They need to go to a vet ophthalmologist pronto. He may have a tumor in that eye.

Cornell uses laser surgery for melanoma. Saves the eye and works well. Not sure if laser can be used for glaucoma.