Experience with XEN or GATT eye surgery to reduce pressure

I have had glaucoma for over 30 years and am now on the maximum drops but the pressure is starting to rise again. Two possible surgeries have been proposed by different glaucoma specialists. XEN involves a tiny flexible tube the size of an eye lash inserted inside the eye coming out very close to the surface of the eye under the upper eye lid to allow fluid to drain easier. GATT also involves a tube inserted inside the eye to redirect fluid bypassing clogged drain. I would like to hear from patients and doctors what they think of these. Both have lots of pros and cons. I've already lost central vision in one eye and would like to keep good vision in the other eye. I am 75 and hope to need my vision for another 15-20 years.