Tonometry is the procedure eye care professionals perform to determine the intraocular pressure (IOP), the fluid pressure inside the eye.

We perform applanation tonometry (no puff of air!) to test the pressure inside the eye. It provides us with the ocular pressure, which is normally less than or equal to 21 mmHG. When pressures rise above this mark, further testing for glaucoma or ocular hypertension is often necessary.