Pretest - non-contact tonometer

How does a non-contact tonometer work? Non-contact (or air-puff) method A brief puff of air is blown at your eye. You will hear the puffing sound and feel a coolness or mild pressure on your eye. The tonometer records the intraocular pressure (IOP) from the change in the light reflected off the cornea as it is indented by the air puff.