A patient has tonometer test results of 28 mmHg. Which explanation by the nurse

4 -- The tonometer is a noninvasive tool to measure the anterior pressure that can build up with glaucoma from overproduction of aqueous humor or decreased drainage from blockage of the canal of Schlemm. Either condition can be treated with surgery or drug management. A measurement of 28 mm Hg is above the normal range of 12-15 mmHg or 15-20 mmHg. A tonometer measures the pressure in the anterior, not the posterior, chamber of the eye. Medication can be used to reduce the pressures in the anterior chamber; posterior fluid (vitreous humor) is not replaced. A tonometer measures eye pressures, and it has nothing to do with the semicircular canal functions in the inner ear. A tympanogram measures the pressure behind the tympanic membrane. A tonometer measures eye pressures and has nothing to do with ear pressure. A tympanogram measures pressure on the tympanic membrane, and can be increased by pressure from fluids with mastoiditis.