Source: Dallas TX
This one is used to measure the pressure within the eye and it is done using an instrument called a tonometer. The doctor places a few eye drops in the eye and then puts pressure on the eyeball with a warm puff of air.
Glaucoma damages the optic nerve and this test is to see if there is any damage. The doctor uses eye drops to dilate your pupil so that he can see the optic nerve in the back. He then looks into your eye using a small microscope. If he finds that your eye pressure is high and the optic nerve doesnt look normal then he will order two more tests just to be sure that he has a glaucoma diagnosis.