Most people with intraocular pressure (IOP) in the low 20's do not develop glaucoma
So my IOP in my left eye is 21 and the IOP in my right eye is 22.5... I've just been told that there NO further progression or damage to my eyes
I have glaucoma now in my right eye, but it took many years of elevated IOP before the optic nerve was affected.
Back in 2009 my right eye IOP was around 24 (normal is <20) but the visual field and optic nerve imaging tests showed no issues.
If your IOP stays above normal in one or both eyes, the opthalmologist should do those extra tests each year to monitor for glaucoma and hopefully catch it really early and prescribe the IOP lowering eye drops.
Unfortunately, my eye doctor back in 2010 retired and I delayed finding a new one and getting a full eye exam for 3 years and by then my right eye's optic nerve already had some damage in one quadrant. The eye drops taken for the past 3.5 years has kept it from getting any worse, but I wish I had gotten annual eye exams during that critical period for a few years after my eye was known to be higher than normal pressure.
So I recommend get annual eye exams from now on to keep your eye's pressure monitored and also get the annual extra tests for visual field and optic nerve imaging to catch it really early. It could take years of higher pressure to affect the optic nerve, but you can't predict when that will happen!