You don't want to have untreated glaucoma. Hopefully you are getting regular screens if you are at risk, not just pressure readings, but visual fields, optic nerve inspections, GDx, etc...
If you actually do have glaucoma, it's a special issuance. As long as your visual fields are normal and you have the necessary acuity to qualify for the level of medical you are seeking, I believe you can get issued. The FAA only takes the Humphrey Visual Fields test (this is a test that many opthamologists have, essentially you stick your head in this machine and it presents flashing lights at various positions that you indicate you saw by clicking a button, while it also tracks your gaze to make sure you're still looking at the center of the target).
In most cases the AME can do an AASI right during your exam.
Use of certain drugs (eye drops, etc...) can be used without necessarily being disqualifying.
Dr. Bruce will be along with the official answer.