This corresponds to a high pressure. Less air inside the tire allows you to more easily indent it, which would correspond to a lower pressure. Normal intraocular pressures average between 12-20 mm Hg. The mm Hg refers to millimeters of mercury, which is a scale for recording the eye pressure. Usually, the higher the pressure, the more risk to the optic nerve.
Eye pressures can vary hourly, daily, and weekly.
Normal fluid consumption does not pose a threat to a patient s intraocular pressure. These daily fluctuations are normal and should not affect your glaucoma on a long-term basis. These tonometers involve measurements taken on the cornea, the clear surface of the eye that covers the iris and lets light enter the eye. The applanation tonometer is considered the most accurate of all the instruments, but the patient must have a clear, regularly shaped cornea for it to give an accurate reading. Before a reading is taken with an applanation tonometer, the patient receives a drop that contains a numbing agent and a colored stain called fluorescein.