My darling rat terrier got glaucoma at age 13 in one eye. I took her to 2 canine ophthalmologists, both recommended medication and then removal of the diseased eye once pressure reached a certain level. 6 months later, the pressure could not be controlled by the meds, so we had her eye removed, a prosthetic inserted in the socket and lid stitched shut. She was fine upon awakening from the anesthesia. Do not opt for the "glass eye" which is prone to infections. Do not just do nothing, the pressure will eventually cause a permanent migraine for your sweet dog. The one-eyed dog looks like she is blinking.
Here's the bad news, 18 moths later she developed glaucoma in 2nd eye that I had been administering prophylactic drops at the 1st sign of glaucoma in 1st eye. Not uncommon. We had the 2nd eye removed. The surgery went well, but she had a much harder time as a suddenly blind dog. 6 months later with lots of love, much talking and verbal cues she gets around our home and yard well. I take her on leash walks every day. She is 16 and as an old dog sleeps more, so exercise is important.
She has been a wonderful dog. I have no regrets in caring for her in her senior years.
BTW, cataracts cause cloudy eyes and are OK not to treat even though the dog will go blind. Glaucoma either looks like a bloodshot eye or no visible signs. Glaucoma clues are petting dog on head and she yelps, or rubbing eyes with paws or head along soft surface. Earlier treatment can preserve eye for much longer.