Hi Chris,
Increased IOP with a puff tonometer is quite normal. They are not as accurate as contact tonometers and use to give readings increased by +1 or +2. Having said that, the numbers mean little if you do not compensate them with the corneal thickness. A cornea thicker than 540 µm will increase the readings and a thinner one will decrease them. For example a 600 µm cornea will produce a +4 Hg mm reading, so if the reading was 23 the real IOP is 19. (look for a table with your browser).
A moderately elevated IOP does not translate into glaucoma. You need optic nerve damage (measured with an OCT), thinning of the GCL, affected VF, and sometimes elevated IOP, as a "normal" IOP can also produce glaucoma in some individuals (called normal tension glaucoma).
My advice is: forget about cheap optometrist review (typical in some undermanned countries)and get into good ophthalmologist hands.