How long would someone with glaucoma last without going blind?

Glaucoma : Is incurable, but treatable. Most people with glaucoma respond well to treatment which halts the progression of the disease. A few, however, progress despite treatment.

Variable: Some glaucomas are very slow to progress and others move rapidly. It depends upon how high the pressure is, how strong the resistance of the circulation at the back of the eye, and of course whether the problem is recognized and treated properly. Most with glaucoma do not go blind.