Ocular tonometry
（重定向自Tonometer）
![](/Images/godic/202502/16/Patient_and_tonometer4629.jpg")
![The slit lamp of a Goldmann tonometer](/Images/godic/202502/16/Slit_lamp4629.jpg")
![Semicircles seen during Goldmann tonometry through slit lamp](/Images/godic/202502/16/Goldmann_mires4629.jpg")
![The PASCAL dynamic contour tonometer](/Images/godic/202502/16/PASCAL_tonometer4629.jpg")
Tonometry is the procedure eye care professionals perform to determine the intraocular pressure (IOP), the fluid pressure inside the eye. It is an important test in the evaluation of patients at risk from glaucoma. Most tonometers are calibrated to measure pressure in millimeters of mercury (mmHg).