How It Is Done continued...
rub your eyes for 30 minutes until the numbing medicine has worn off.
Noncontact (or air-puff) method
This type of
tonometry is done by an ophthalmologist or an optometrist. You do not need
drops to numb your eye for this method.
You will rest your chin on
a padded support and stare straight into the machine. 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. The test may be done several times for each
How It Feels
Tonometry should not cause any eye pain.
Your doctor will use eyedrops to numb the surface of your eyes so that you will
not feel the tonometer during the test. You may have a scratchy feeling on your
cornea. This usually goes away in 24 hours.
Some people become
anxious when the tonometer needs to be touched to the eye. In air-puff
tonometry, only a puff of air touches the eye.
There is a very slight risk that your cornea
may be scratched during the methods that involve touching a tonometer to your
eye. Rubbing your eyes before the numbing eyedrops wear off increases the risk of
scratching the cornea. If tonometry causes a scratch on the cornea, your eye
may be uncomfortable until the scratch heals, which normally takes about a
There is also a very small risk of an eye infection or an
allergic reaction to the eyedrops used to numb your
With the air-puff (noncontact) method, there is no risk of
scratches or infection, since nothing but air touches your eyes. But this
method is not the best way to measure intraocular pressure.
should not have any eye pain or vision problems after tonometry. Call your
doctor if you feel any eye pain during the test or for 48 hours after the